drm/i915: Make driver less chatty

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / gpu / drm / i915 / intel_lvds.c

/*
 * Copyright © 2006-2007 Intel Corporation
 * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 *      Eric Anholt <eric@anholt.net>
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */

#include <linux/dmi.h>
#include <linux/i2c.h>
#include "drmP.h"
#include "drm.h"
#include "drm_crtc.h"
#include "drm_edid.h"
#include "intel_drv.h"
#include "i915_drm.h"
#include "i915_drv.h"

#define I915_LVDS "i915_lvds"

/*
 * the following four scaling options are defined.
 * #define DRM_MODE_SCALE_NON_GPU       0
 * #define DRM_MODE_SCALE_FULLSCREEN    1
 * #define DRM_MODE_SCALE_NO_SCALE      2
 * #define DRM_MODE_SCALE_ASPECT        3
 */

/* Private structure for the integrated LVDS support */
struct intel_lvds_priv {
        int fitting_mode;
        u32 pfit_control;
        u32 pfit_pgm_ratios;
};

/**
 * Sets the backlight level.
 *
 * \param level backlight level, from 0 to intel_lvds_get_max_backlight().
 */
static void intel_lvds_set_backlight(struct drm_device *dev, int level)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 blc_pwm_ctl, reg;

        if (IS_IGDNG(dev))
                reg = BLC_PWM_CPU_CTL;
        else
                reg = BLC_PWM_CTL;

        blc_pwm_ctl = I915_READ(reg) & ~BACKLIGHT_DUTY_CYCLE_MASK;
        I915_WRITE(reg, (blc_pwm_ctl |
                                 (level << BACKLIGHT_DUTY_CYCLE_SHIFT)));
}

/**
 * Returns the maximum level of the backlight duty cycle field.
 */
static u32 intel_lvds_get_max_backlight(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 reg;

        if (IS_IGDNG(dev))
                reg = BLC_PWM_PCH_CTL2;
        else
                reg = BLC_PWM_CTL;

        return ((I915_READ(reg) & BACKLIGHT_MODULATION_FREQ_MASK) >>
                BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
}

/**
 * Sets the power state for the panel.
 */
static void intel_lvds_set_power(struct drm_device *dev, bool on)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp_status, ctl_reg, status_reg;

        if (IS_IGDNG(dev)) {
                ctl_reg = PCH_PP_CONTROL;
                status_reg = PCH_PP_STATUS;
        } else {
                ctl_reg = PP_CONTROL;
                status_reg = PP_STATUS;
        }

        if (on) {
                I915_WRITE(ctl_reg, I915_READ(ctl_reg) |
                           POWER_TARGET_ON);
                do {
                        pp_status = I915_READ(status_reg);
                } while ((pp_status & PP_ON) == 0);

                intel_lvds_set_backlight(dev, dev_priv->backlight_duty_cycle);
        } else {
                intel_lvds_set_backlight(dev, 0);

                I915_WRITE(ctl_reg, I915_READ(ctl_reg) &
                           ~POWER_TARGET_ON);
                do {
                        pp_status = I915_READ(status_reg);
                } while (pp_status & PP_ON);
        }
}

static void intel_lvds_dpms(struct drm_encoder *encoder, int mode)
{
        struct drm_device *dev = encoder->dev;

        if (mode == DRM_MODE_DPMS_ON)
                intel_lvds_set_power(dev, true);
        else
                intel_lvds_set_power(dev, false);

        /* XXX: We never power down the LVDS pairs. */
}

static void intel_lvds_save(struct drm_connector *connector)
{
        struct drm_device *dev = connector->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp_on_reg, pp_off_reg, pp_ctl_reg, pp_div_reg;
        u32 pwm_ctl_reg;

        if (IS_IGDNG(dev)) {
                pp_on_reg = PCH_PP_ON_DELAYS;
                pp_off_reg = PCH_PP_OFF_DELAYS;
                pp_ctl_reg = PCH_PP_CONTROL;
                pp_div_reg = PCH_PP_DIVISOR;
                pwm_ctl_reg = BLC_PWM_CPU_CTL;
        } else {
                pp_on_reg = PP_ON_DELAYS;
                pp_off_reg = PP_OFF_DELAYS;
                pp_ctl_reg = PP_CONTROL;
                pp_div_reg = PP_DIVISOR;
                pwm_ctl_reg = BLC_PWM_CTL;
        }

        dev_priv->savePP_ON = I915_READ(pp_on_reg);
        dev_priv->savePP_OFF = I915_READ(pp_off_reg);
        dev_priv->savePP_CONTROL = I915_READ(pp_ctl_reg);
        dev_priv->savePP_DIVISOR = I915_READ(pp_div_reg);
        dev_priv->saveBLC_PWM_CTL = I915_READ(pwm_ctl_reg);
        dev_priv->backlight_duty_cycle = (dev_priv->saveBLC_PWM_CTL &
                                       BACKLIGHT_DUTY_CYCLE_MASK);

        /*
         * If the light is off at server startup, just make it full brightness
         */
        if (dev_priv->backlight_duty_cycle == 0)
                dev_priv->backlight_duty_cycle =
                        intel_lvds_get_max_backlight(dev);
}

static void intel_lvds_restore(struct drm_connector *connector)
{
        struct drm_device *dev = connector->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp_on_reg, pp_off_reg, pp_ctl_reg, pp_div_reg;
        u32 pwm_ctl_reg;

        if (IS_IGDNG(dev)) {
                pp_on_reg = PCH_PP_ON_DELAYS;
                pp_off_reg = PCH_PP_OFF_DELAYS;
                pp_ctl_reg = PCH_PP_CONTROL;
                pp_div_reg = PCH_PP_DIVISOR;
                pwm_ctl_reg = BLC_PWM_CPU_CTL;
        } else {
                pp_on_reg = PP_ON_DELAYS;
                pp_off_reg = PP_OFF_DELAYS;
                pp_ctl_reg = PP_CONTROL;
                pp_div_reg = PP_DIVISOR;
                pwm_ctl_reg = BLC_PWM_CTL;
        }

        I915_WRITE(pwm_ctl_reg, dev_priv->saveBLC_PWM_CTL);
        I915_WRITE(pp_on_reg, dev_priv->savePP_ON);
        I915_WRITE(pp_off_reg, dev_priv->savePP_OFF);
        I915_WRITE(pp_div_reg, dev_priv->savePP_DIVISOR);
        I915_WRITE(pp_ctl_reg, dev_priv->savePP_CONTROL);
        if (dev_priv->savePP_CONTROL & POWER_TARGET_ON)
                intel_lvds_set_power(dev, true);
        else
                intel_lvds_set_power(dev, false);
}

static int intel_lvds_mode_valid(struct drm_connector *connector,
                                 struct drm_display_mode *mode)
{
        struct drm_device *dev = connector->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_display_mode *fixed_mode = dev_priv->panel_fixed_mode;

        if (fixed_mode) {
                if (mode->hdisplay > fixed_mode->hdisplay)
                        return MODE_PANEL;
                if (mode->vdisplay > fixed_mode->vdisplay)
                        return MODE_PANEL;
        }

        return MODE_OK;
}

static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
                                  struct drm_display_mode *mode,
                                  struct drm_display_mode *adjusted_mode)
{
        /*
         * float point operation is not supported . So the PANEL_RATIO_FACTOR
         * is defined, which can avoid the float point computation when
         * calculating the panel ratio.
         */
#define PANEL_RATIO_FACTOR 8192
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
        struct drm_encoder *tmp_encoder;
        struct intel_output *intel_output = enc_to_intel_output(encoder);
        struct intel_lvds_priv *lvds_priv = intel_output->dev_priv;
        u32 pfit_control = 0, pfit_pgm_ratios = 0;
        int left_border = 0, right_border = 0, top_border = 0;
        int bottom_border = 0;
        bool border = 0;
        int panel_ratio, desired_ratio, vert_scale, horiz_scale;
        int horiz_ratio, vert_ratio;
        u32 hsync_width, vsync_width;
        u32 hblank_width, vblank_width;
        u32 hsync_pos, vsync_pos;

        /* Should never happen!! */
        if (!IS_I965G(dev) && intel_crtc->pipe == 0) {
                DRM_ERROR("Can't support LVDS on pipe A\n");
                return false;
        }

        /* Should never happen!! */
        list_for_each_entry(tmp_encoder, &dev->mode_config.encoder_list, head) {
                if (tmp_encoder != encoder && tmp_encoder->crtc == encoder->crtc) {
                        DRM_ERROR("Can't enable LVDS and another "
                               "encoder on the same pipe\n");
                        return false;
                }
        }
        /* If we don't have a panel mode, there is nothing we can do */
        if (dev_priv->panel_fixed_mode == NULL)
                return true;
        /*
         * If we have timings from the BIOS for the panel, put them in
         * to the adjusted mode.  The CRTC will be set up for this mode,
         * with the panel scaling set up to source from the H/VDisplay
         * of the original mode.
         */
        if (dev_priv->panel_fixed_mode != NULL) {
                adjusted_mode->hdisplay = dev_priv->panel_fixed_mode->hdisplay;
                adjusted_mode->hsync_start =
                        dev_priv->panel_fixed_mode->hsync_start;
                adjusted_mode->hsync_end =
                        dev_priv->panel_fixed_mode->hsync_end;
                adjusted_mode->htotal = dev_priv->panel_fixed_mode->htotal;
                adjusted_mode->vdisplay = dev_priv->panel_fixed_mode->vdisplay;
                adjusted_mode->vsync_start =
                        dev_priv->panel_fixed_mode->vsync_start;
                adjusted_mode->vsync_end =
                        dev_priv->panel_fixed_mode->vsync_end;
                adjusted_mode->vtotal = dev_priv->panel_fixed_mode->vtotal;
                adjusted_mode->clock = dev_priv->panel_fixed_mode->clock;
                drm_mode_set_crtcinfo(adjusted_mode, CRTC_INTERLACE_HALVE_V);
        }

        /* Make sure pre-965s set dither correctly */
        if (!IS_I965G(dev)) {
                if (dev_priv->panel_wants_dither || dev_priv->lvds_dither)
                        pfit_control |= PANEL_8TO6_DITHER_ENABLE;
        }

        /* Native modes don't need fitting */
        if (adjusted_mode->hdisplay == mode->hdisplay &&
                        adjusted_mode->vdisplay == mode->vdisplay) {
                pfit_pgm_ratios = 0;
                border = 0;
                goto out;
        }

        /* 965+ wants fuzzy fitting */
        if (IS_I965G(dev))
                pfit_control |= (intel_crtc->pipe << PFIT_PIPE_SHIFT) |
                                        PFIT_FILTER_FUZZY;

        hsync_width = adjusted_mode->crtc_hsync_end -
                                        adjusted_mode->crtc_hsync_start;
        vsync_width = adjusted_mode->crtc_vsync_end -
                                        adjusted_mode->crtc_vsync_start;
        hblank_width = adjusted_mode->crtc_hblank_end -
                                        adjusted_mode->crtc_hblank_start;
        vblank_width = adjusted_mode->crtc_vblank_end -
                                        adjusted_mode->crtc_vblank_start;
        /*
         * Deal with panel fitting options. Figure out how to stretch the
         * image based on its aspect ratio & the current panel fitting mode.
         */
        panel_ratio = adjusted_mode->hdisplay * PANEL_RATIO_FACTOR /
                                adjusted_mode->vdisplay;
        desired_ratio = mode->hdisplay * PANEL_RATIO_FACTOR /
                                mode->vdisplay;
        /*
         * Enable automatic panel scaling for non-native modes so that they fill
         * the screen.  Should be enabled before the pipe is enabled, according
         * to register description and PRM.
         * Change the value here to see the borders for debugging
         */
        I915_WRITE(BCLRPAT_A, 0);
        I915_WRITE(BCLRPAT_B, 0);

        switch (lvds_priv->fitting_mode) {
        case DRM_MODE_SCALE_NO_SCALE:
                /*
                 * For centered modes, we have to calculate border widths &
                 * heights and modify the values programmed into the CRTC.
                 */
                left_border = (adjusted_mode->hdisplay - mode->hdisplay) / 2;
                right_border = left_border;
                if (mode->hdisplay & 1)
                        right_border++;
                top_border = (adjusted_mode->vdisplay - mode->vdisplay) / 2;
                bottom_border = top_border;
                if (mode->vdisplay & 1)
                        bottom_border++;
                /* Set active & border values */
                adjusted_mode->crtc_hdisplay = mode->hdisplay;
                /* Keep the boder be even */
                if (right_border & 1)
                        right_border++;
                /* use the border directly instead of border minuse one */
                adjusted_mode->crtc_hblank_start = mode->hdisplay +
                                                right_border;
                /* keep the blank width constant */
                adjusted_mode->crtc_hblank_end =
                        adjusted_mode->crtc_hblank_start + hblank_width;
                /* get the hsync pos relative to hblank start */
                hsync_pos = (hblank_width - hsync_width) / 2;
                /* keep the hsync pos be even */
                if (hsync_pos & 1)
                        hsync_pos++;
                adjusted_mode->crtc_hsync_start =
                                adjusted_mode->crtc_hblank_start + hsync_pos;
                /* keep the hsync width constant */
                adjusted_mode->crtc_hsync_end =
                                adjusted_mode->crtc_hsync_start + hsync_width;
                adjusted_mode->crtc_vdisplay = mode->vdisplay;
                /* use the border instead of border minus one */
                adjusted_mode->crtc_vblank_start = mode->vdisplay +
                                                bottom_border;
                /* keep the vblank width constant */
                adjusted_mode->crtc_vblank_end =
                                adjusted_mode->crtc_vblank_start + vblank_width;
                /* get the vsync start postion relative to vblank start */
                vsync_pos = (vblank_width - vsync_width) / 2;
                adjusted_mode->crtc_vsync_start =
                                adjusted_mode->crtc_vblank_start + vsync_pos;
                /* keep the vsync width constant */
                adjusted_mode->crtc_vsync_end =
                                adjusted_mode->crtc_vblank_start + vsync_width;
                border = 1;
                break;
        case DRM_MODE_SCALE_ASPECT:
                /* Scale but preserve the spect ratio */
                pfit_control |= PFIT_ENABLE;
                if (IS_I965G(dev)) {
                        /* 965+ is easy, it does everything in hw */
                        if (panel_ratio > desired_ratio)
                                pfit_control |= PFIT_SCALING_PILLAR;
                        else if (panel_ratio < desired_ratio)
                                pfit_control |= PFIT_SCALING_LETTER;
                        else
                                pfit_control |= PFIT_SCALING_AUTO;
                } else {
                        /*
                         * For earlier chips we have to calculate the scaling
                         * ratio by hand and program it into the
                         * PFIT_PGM_RATIO register
                         */
                        u32 horiz_bits, vert_bits, bits = 12;
                        horiz_ratio = mode->hdisplay * PANEL_RATIO_FACTOR/
                                                adjusted_mode->hdisplay;
                        vert_ratio = mode->vdisplay * PANEL_RATIO_FACTOR/
                                                adjusted_mode->vdisplay;
                        horiz_scale = adjusted_mode->hdisplay *
                                        PANEL_RATIO_FACTOR / mode->hdisplay;
                        vert_scale = adjusted_mode->vdisplay *
                                        PANEL_RATIO_FACTOR / mode->vdisplay;

                        /* retain aspect ratio */
                        if (panel_ratio > desired_ratio) { /* Pillar */
                                u32 scaled_width;
                                scaled_width = mode->hdisplay * vert_scale /
                                                PANEL_RATIO_FACTOR;
                                horiz_ratio = vert_ratio;
                                pfit_control |= (VERT_AUTO_SCALE |
                                                 VERT_INTERP_BILINEAR |
                                                 HORIZ_INTERP_BILINEAR);
                                /* Pillar will have left/right borders */
                                left_border = (adjusted_mode->hdisplay -
                                                scaled_width) / 2;
                                right_border = left_border;
                                if (mode->hdisplay & 1) /* odd resolutions */
                                        right_border++;
                                /* keep the border be even */
                                if (right_border & 1)
                                        right_border++;
                                adjusted_mode->crtc_hdisplay = scaled_width;
                                /* use border instead of border minus one */
                                adjusted_mode->crtc_hblank_start =
                                        scaled_width + right_border;
                                /* keep the hblank width constant */
                                adjusted_mode->crtc_hblank_end =
                                        adjusted_mode->crtc_hblank_start +
                                                        hblank_width;
                                /*
                                 * get the hsync start pos relative to
                                 * hblank start
                                 */
                                hsync_pos = (hblank_width - hsync_width) / 2;
                                /* keep the hsync_pos be even */
                                if (hsync_pos & 1)
                                        hsync_pos++;
                                adjusted_mode->crtc_hsync_start =
                                        adjusted_mode->crtc_hblank_start +
                                                        hsync_pos;
                                /* keept hsync width constant */
                                adjusted_mode->crtc_hsync_end =
                                        adjusted_mode->crtc_hsync_start +
                                                        hsync_width;
                                border = 1;
                        } else if (panel_ratio < desired_ratio) { /* letter */
                                u32 scaled_height = mode->vdisplay *
                                        horiz_scale / PANEL_RATIO_FACTOR;
                                vert_ratio = horiz_ratio;
                                pfit_control |= (HORIZ_AUTO_SCALE |
                                                 VERT_INTERP_BILINEAR |
                                                 HORIZ_INTERP_BILINEAR);
                                /* Letterbox will have top/bottom border */
                                top_border = (adjusted_mode->vdisplay -
                                        scaled_height) / 2;
                                bottom_border = top_border;
                                if (mode->vdisplay & 1)
                                        bottom_border++;
                                adjusted_mode->crtc_vdisplay = scaled_height;
                                /* use border instead of border minus one */
                                adjusted_mode->crtc_vblank_start =
                                        scaled_height + bottom_border;
                                /* keep the vblank width constant */
                                adjusted_mode->crtc_vblank_end =
                                        adjusted_mode->crtc_vblank_start +
                                                        vblank_width;
                                /*
                                 * get the vsync start pos relative to
                                 * vblank start
                                 */
                                vsync_pos = (vblank_width - vsync_width) / 2;
                                adjusted_mode->crtc_vsync_start =
                                        adjusted_mode->crtc_vblank_start +
                                                        vsync_pos;
                                /* keep the vsync width constant */
                                adjusted_mode->crtc_vsync_end =
                                        adjusted_mode->crtc_vsync_start +
                                                        vsync_width;
                                border = 1;
                        } else {
                        /* Aspects match, Let hw scale both directions */
                                pfit_control |= (VERT_AUTO_SCALE |
                                                 HORIZ_AUTO_SCALE |
                                                 VERT_INTERP_BILINEAR |
                                                 HORIZ_INTERP_BILINEAR);
                        }
                        horiz_bits = (1 << bits) * horiz_ratio /
                                        PANEL_RATIO_FACTOR;
                        vert_bits = (1 << bits) * vert_ratio /
                                        PANEL_RATIO_FACTOR;
                        pfit_pgm_ratios =
                                ((vert_bits << PFIT_VERT_SCALE_SHIFT) &
                                                PFIT_VERT_SCALE_MASK) |
                                ((horiz_bits << PFIT_HORIZ_SCALE_SHIFT) &
                                                PFIT_HORIZ_SCALE_MASK);
                }
                break;

        case DRM_MODE_SCALE_FULLSCREEN:
                /*
                 * Full scaling, even if it changes the aspect ratio.
                 * Fortunately this is all done for us in hw.
                 */
                pfit_control |= PFIT_ENABLE;
                if (IS_I965G(dev))
                        pfit_control |= PFIT_SCALING_AUTO;
                else
                        pfit_control |= (VERT_AUTO_SCALE | HORIZ_AUTO_SCALE |
                                         VERT_INTERP_BILINEAR |
                                         HORIZ_INTERP_BILINEAR);
                break;
        default:
                break;
        }

out:
        lvds_priv->pfit_control = pfit_control;
        lvds_priv->pfit_pgm_ratios = pfit_pgm_ratios;
        /*
         * XXX: It would be nice to support lower refresh rates on the
         * panels to reduce power consumption, and perhaps match the
         * user's requested refresh rate.
         */

        return true;
}

static void intel_lvds_prepare(struct drm_encoder *encoder)
{
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 reg;

        if (IS_IGDNG(dev))
                reg = BLC_PWM_CPU_CTL;
        else
                reg = BLC_PWM_CTL;

        dev_priv->saveBLC_PWM_CTL = I915_READ(reg);
        dev_priv->backlight_duty_cycle = (dev_priv->saveBLC_PWM_CTL &
                                       BACKLIGHT_DUTY_CYCLE_MASK);

        intel_lvds_set_power(dev, false);
}

static void intel_lvds_commit( struct drm_encoder *encoder)
{
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (dev_priv->backlight_duty_cycle == 0)
                dev_priv->backlight_duty_cycle =
                        intel_lvds_get_max_backlight(dev);

        intel_lvds_set_power(dev, true);
}

static void intel_lvds_mode_set(struct drm_encoder *encoder,
                                struct drm_display_mode *mode,
                                struct drm_display_mode *adjusted_mode)
{
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_output *intel_output = enc_to_intel_output(encoder);
        struct intel_lvds_priv *lvds_priv = intel_output->dev_priv;

        /*
         * The LVDS pin pair will already have been turned on in the
         * intel_crtc_mode_set since it has a large impact on the DPLL
         * settings.
         */

        /* No panel fitting yet, fixme */
        if (IS_IGDNG(dev))
                return;

        /*
         * Enable automatic panel scaling so that non-native modes fill the
         * screen.  Should be enabled before the pipe is enabled, according to
         * register description and PRM.
         */
        I915_WRITE(PFIT_PGM_RATIOS, lvds_priv->pfit_pgm_ratios);
        I915_WRITE(PFIT_CONTROL, lvds_priv->pfit_control);
}

/**
 * Detect the LVDS connection.
 *
 * This always returns CONNECTOR_STATUS_CONNECTED.  This connector should only have
 * been set up if the LVDS was actually connected anyway.
 */
static enum drm_connector_status intel_lvds_detect(struct drm_connector *connector)
{
        return connector_status_connected;
}

/**
 * Return the list of DDC modes if available, or the BIOS fixed mode otherwise.
 */
static int intel_lvds_get_modes(struct drm_connector *connector)
{
        struct drm_device *dev = connector->dev;
        struct intel_output *intel_output = to_intel_output(connector);
        struct drm_i915_private *dev_priv = dev->dev_private;
        int ret = 0;

        ret = intel_ddc_get_modes(intel_output);

        if (ret)
                return ret;

        /* Didn't get an EDID, so
         * Set wide sync ranges so we get all modes
         * handed to valid_mode for checking
         */
        connector->display_info.min_vfreq = 0;
        connector->display_info.max_vfreq = 200;
        connector->display_info.min_hfreq = 0;
        connector->display_info.max_hfreq = 200;

        if (dev_priv->panel_fixed_mode != NULL) {
                struct drm_display_mode *mode;

                mode = drm_mode_duplicate(dev, dev_priv->panel_fixed_mode);
                drm_mode_probed_add(connector, mode);

                return 1;
        }

        return 0;
}

/**
 * intel_lvds_destroy - unregister and free LVDS structures
 * @connector: connector to free
 *
 * Unregister the DDC bus for this connector then free the driver private
 * structure.
 */
static void intel_lvds_destroy(struct drm_connector *connector)
{
        struct intel_output *intel_output = to_intel_output(connector);

        if (intel_output->ddc_bus)
                intel_i2c_destroy(intel_output->ddc_bus);
        drm_sysfs_connector_remove(connector);
        drm_connector_cleanup(connector);
        kfree(connector);
}

static int intel_lvds_set_property(struct drm_connector *connector,
                                   struct drm_property *property,
                                   uint64_t value)
{
        struct drm_device *dev = connector->dev;
        struct intel_output *intel_output =
                        to_intel_output(connector);

        if (property == dev->mode_config.scaling_mode_property &&
                                connector->encoder) {
                struct drm_crtc *crtc = connector->encoder->crtc;
                struct intel_lvds_priv *lvds_priv = intel_output->dev_priv;
                if (value == DRM_MODE_SCALE_NON_GPU) {
                        DRM_DEBUG_KMS(I915_LVDS,
                                        "non_GPU property is unsupported\n");
                        return 0;
                }
                if (lvds_priv->fitting_mode == value) {
                        /* the LVDS scaling property is not changed */
                        return 0;
                }
                lvds_priv->fitting_mode = value;
                if (crtc && crtc->enabled) {
                        /*
                         * If the CRTC is enabled, the display will be changed
                         * according to the new panel fitting mode.
                         */
                        drm_crtc_helper_set_mode(crtc, &crtc->mode,
                                crtc->x, crtc->y, crtc->fb);
                }
        }

        return 0;
}

static const struct drm_encoder_helper_funcs intel_lvds_helper_funcs = {
        .dpms = intel_lvds_dpms,
        .mode_fixup = intel_lvds_mode_fixup,
        .prepare = intel_lvds_prepare,
        .mode_set = intel_lvds_mode_set,
        .commit = intel_lvds_commit,
};

static const struct drm_connector_helper_funcs intel_lvds_connector_helper_funcs = {
        .get_modes = intel_lvds_get_modes,
        .mode_valid = intel_lvds_mode_valid,
        .best_encoder = intel_best_encoder,
};

static const struct drm_connector_funcs intel_lvds_connector_funcs = {
        .dpms = drm_helper_connector_dpms,
        .save = intel_lvds_save,
        .restore = intel_lvds_restore,
        .detect = intel_lvds_detect,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .set_property = intel_lvds_set_property,
        .destroy = intel_lvds_destroy,
};


static void intel_lvds_enc_destroy(struct drm_encoder *encoder)
{
        drm_encoder_cleanup(encoder);
}

static const struct drm_encoder_funcs intel_lvds_enc_funcs = {
        .destroy = intel_lvds_enc_destroy,
};

static int __init intel_no_lvds_dmi_callback(const struct dmi_system_id *id)
{
        DRM_DEBUG_KMS(I915_LVDS,
                      "Skipping LVDS initialization for %s\n", id->ident);
        return 1;
}

/* These systems claim to have LVDS, but really don't */
static const struct dmi_system_id intel_no_lvds[] = {
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Apple Mac Mini (Core series)",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Apple"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Macmini1,1"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Apple Mac Mini (Core 2 series)",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Apple"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Macmini2,1"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "MSI IM-945GSE-A",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "MSI"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "A9830IMS"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Dell Studio Hybrid",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Studio Hybrid 140g"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "AOpen Mini PC",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "AOpen"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "i965GMx-IF"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Aopen i945GTt-VFA",
                .matches = {
                        DMI_MATCH(DMI_PRODUCT_VERSION, "AO00001JW"),
                },
        },

        { }     /* terminating entry */
};

/**
 * intel_lvds_init - setup LVDS connectors on this device
 * @dev: drm device
 *
 * Create the connector, register the LVDS DDC bus, and try to figure out what
 * modes we can display on the LVDS panel (if present).
 */
void intel_lvds_init(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_output *intel_output;
        struct drm_connector *connector;
        struct drm_encoder *encoder;
        struct drm_display_mode *scan; /* *modes, *bios_mode; */
        struct drm_crtc *crtc;
        struct intel_lvds_priv *lvds_priv;
        u32 lvds;
        int pipe, gpio = GPIOC;

        /* Skip init on machines we know falsely report LVDS */
        if (dmi_check_system(intel_no_lvds))
                return;

        if (IS_IGDNG(dev)) {
                if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0)
                        return;
                gpio = PCH_GPIOC;
        }

        intel_output = kzalloc(sizeof(struct intel_output) +
                                sizeof(struct intel_lvds_priv), GFP_KERNEL);
        if (!intel_output) {
                return;
        }

        connector = &intel_output->base;
        encoder = &intel_output->enc;
        drm_connector_init(dev, &intel_output->base, &intel_lvds_connector_funcs,
                           DRM_MODE_CONNECTOR_LVDS);

        drm_encoder_init(dev, &intel_output->enc, &intel_lvds_enc_funcs,
                         DRM_MODE_ENCODER_LVDS);

        drm_mode_connector_attach_encoder(&intel_output->base, &intel_output->enc);
        intel_output->type = INTEL_OUTPUT_LVDS;

        drm_encoder_helper_add(encoder, &intel_lvds_helper_funcs);
        drm_connector_helper_add(connector, &intel_lvds_connector_helper_funcs);
        connector->display_info.subpixel_order = SubPixelHorizontalRGB;
        connector->interlace_allowed = false;
        connector->doublescan_allowed = false;

        lvds_priv = (struct intel_lvds_priv *)(intel_output + 1);
        intel_output->dev_priv = lvds_priv;
        /* create the scaling mode property */
        drm_mode_create_scaling_mode_property(dev);
        /*
         * the initial panel fitting mode will be FULL_SCREEN.
         */

        drm_connector_attach_property(&intel_output->base,
                                      dev->mode_config.scaling_mode_property,
                                      DRM_MODE_SCALE_FULLSCREEN);
        lvds_priv->fitting_mode = DRM_MODE_SCALE_FULLSCREEN;
        /*
         * LVDS discovery:
         * 1) check for EDID on DDC
         * 2) check for VBT data
         * 3) check to see if LVDS is already on
         *    if none of the above, no panel
         * 4) make sure lid is open
         *    if closed, act like it's not there for now
         */

        /* Set up the DDC bus. */
        intel_output->ddc_bus = intel_i2c_create(dev, gpio, "LVDSDDC_C");
        if (!intel_output->ddc_bus) {
                dev_printk(KERN_ERR, &dev->pdev->dev, "DDC bus registration "
                           "failed.\n");
                goto failed;
        }

        /*
         * Attempt to get the fixed panel mode from DDC.  Assume that the
         * preferred mode is the right one.
         */
        intel_ddc_get_modes(intel_output);

        list_for_each_entry(scan, &connector->probed_modes, head) {
                mutex_lock(&dev->mode_config.mutex);
                if (scan->type & DRM_MODE_TYPE_PREFERRED) {
                        dev_priv->panel_fixed_mode =
                                drm_mode_duplicate(dev, scan);
                        mutex_unlock(&dev->mode_config.mutex);
                        goto out;
                }
                mutex_unlock(&dev->mode_config.mutex);
        }

        /* Failed to get EDID, what about VBT? */
        if (dev_priv->lfp_lvds_vbt_mode) {
                mutex_lock(&dev->mode_config.mutex);
                dev_priv->panel_fixed_mode =
                        drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
                mutex_unlock(&dev->mode_config.mutex);
                if (dev_priv->panel_fixed_mode) {
                        dev_priv->panel_fixed_mode->type |=
                                DRM_MODE_TYPE_PREFERRED;
                        goto out;
                }
        }

        /*
         * If we didn't get EDID, try checking if the panel is already turned
         * on.  If so, assume that whatever is currently programmed is the
         * correct mode.
         */

        /* IGDNG: FIXME if still fail, not try pipe mode now */
        if (IS_IGDNG(dev))
                goto failed;

        lvds = I915_READ(LVDS);
        pipe = (lvds & LVDS_PIPEB_SELECT) ? 1 : 0;
        crtc = intel_get_crtc_from_pipe(dev, pipe);

        if (crtc && (lvds & LVDS_PORT_EN)) {
                dev_priv->panel_fixed_mode = intel_crtc_mode_get(dev, crtc);
                if (dev_priv->panel_fixed_mode) {
                        dev_priv->panel_fixed_mode->type |=
                                DRM_MODE_TYPE_PREFERRED;
                        goto out;
                }
        }

        /* If we still don't have a mode after all that, give up. */
        if (!dev_priv->panel_fixed_mode)
                goto failed;

out:
        if (IS_IGDNG(dev)) {
                u32 pwm;
                /* make sure PWM is enabled */
                pwm = I915_READ(BLC_PWM_CPU_CTL2);
                pwm |= (PWM_ENABLE | PWM_PIPE_B);
                I915_WRITE(BLC_PWM_CPU_CTL2, pwm);

                pwm = I915_READ(BLC_PWM_PCH_CTL1);
                pwm |= PWM_PCH_ENABLE;
                I915_WRITE(BLC_PWM_PCH_CTL1, pwm);
        }
        drm_sysfs_connector_add(connector);
        return;

failed:
        DRM_DEBUG_KMS(I915_LVDS, "No LVDS modes found, disabling.\n");
        if (intel_output->ddc_bus)
                intel_i2c_destroy(intel_output->ddc_bus);
        drm_connector_cleanup(connector);
        kfree(intel_output);
}