ahci: disable FPDMA auto-activate optimization on NVIDIA AHCI
commit6eefd62ab7b4fba12b7daa59a0968568e2534365
authorRobert Hancock <hancockrwd@gmail.com>
Wed, 27 Jan 2010 04:33:23 +0000 (26 22:33 -0600)
committerGreg Kroah-Hartman <gregkh@suse.de>
Mon, 15 Mar 2010 15:49:35 +0000 (15 08:49 -0700)
treea0d7369ffcadeb21bf10be918d118bf0925ad495
parent15bd3e21f0b4b12aca0f016cb2d962fc227182e2
ahci: disable FPDMA auto-activate optimization on NVIDIA AHCI

commit 453d3131ec7aab82eaaa8401a50522a337092aa8 upstream.

Mike Cui reported that his system with an NVIDIA MCP79 (aka MCP7A)
chipset stopped working with 2.6.32. The problem appears to be that
2.6.32 now enables the FPDMA auto-activate optimization in the ahci
driver. The drive works fine with this enabled on an Intel AHCI so
this appears to be a chipset bug.  Since MCP79 is a fairly recent
NVIDIA chipset and we don't have any info on whether any other NVIDIA
chipsets have this issue, disable FPDMA AA optimization on all NVIDIA
AHCI controllers for now.

Should address http://bugzilla.kernel.org/show_bug.cgi?id=14922

Signed-off-by: Robert Hancock <hancockrwd@gmail.com>
While-we-investigate-issue-this-patch-looks-good-to-me-by:
Prajakta Gudadhe <pgudadhe@nvidia.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/ata/ahci.c