e1000: Fix RX descriptor low threshold interrupt logic (Alex Williamson)
commitbf16cc8f97ff57db191eec73346ba0333ade342b
authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Fri, 20 Mar 2009 16:13:47 +0000 (20 16:13 +0000)
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Fri, 20 Mar 2009 16:13:47 +0000 (20 16:13 +0000)
tree081ee60c6c9b9b801de4b1bebcfdfdb43821bc8b
parentdc1ded53b8cd9198da193e44b25815cdd2ddb6f5
e1000: Fix RX descriptor low threshold interrupt logic (Alex Williamson)

The RXDMT0 interrupt is supposed to fire when the number of free
RX descriptors drops to some fraction of the total descriptors.
However in practice, it seems like we're adding this interrupt
cause on every RX.  Fix the logic to treat (tail - head) as the
number of free entries rather than the number of used entries.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6864 c046a42c-6fe2-441c-8c8c-71466251a162
hw/e1000.c