On Mon, Mar 22, 2010 at 4:34 PM, Eric Anholt <eric@xxxxxxxxxx> wrote:On Mon, 22 Mar 2010 09:11:06 +0100, Karl Vogel <karl.vogel@xxxxxxxxx> wrote:On Mon, Mar 22, 2010 at 5:20 AM, Eric Anholt <eric@xxxxxxxxxx> wrote:Missed that part of the message. If there's a regression, bisectOn Sat, 20 Mar 2010 14:41:41 +0100, Karl Vogel <karl.vogel@xxxxxxxxx> wrote:That doesnt explain why the box completely locks up on 2.6.34-rc2The 'effect' is that only the mouse pointer works in the X server. TheIf there's some code doing glFlush()es, it's probably that code at
cpu usage on the laptop during the sluggishness is minimal. When I
suspend the game with winedbg, the X server slowly becomes responsive again.
The output from latencytop seems to point to i915 being the culprit:
fault. You don't need to do that unless you're doing frontbuffer
rendering, and if you're doing frontbuffer rendering you should really
be doing backbuffer rendering. I don't see a kernel issue here.
though, where only a cold reboot works.
Apparently the crash was caused by a hardware bug in the intel chipset
which is 8086:2a40 rev 07. While doing the bisect I got an error:
DRHD: handling fault status reg 2
DMAR:[DMA Write] Request device [00:02.0] fault addr dd69a000
DMAR:[fault reason 05] PTE Write access is not set
After some googling around, I found this bugzilla entry which explains it:
The issue appears that the graphics chip is corrupting memory:
"Unfortunately, this particular chipset sometimes reads from the GTT, does the
translation, then writes the translated address back to the _original_ GTT
instead of to the shadow GTT. That's why you're seeing real physical addresses
where you should have 'virtual DMA addresses', and you get the faults. "
Adding "intel_iommu=igfx_off" to the kernel command line resolved the issue.
The fedora kernel automatically disables this when it detects this particular
As for the freeze/slowdown right after booting, sysprof shows that more than 77%
of the time is spent inside: drm_mode_getconnector