On Mon, Feb 27, 2012 at 01:42:43PM +0100, Stanislaw Gruszka wrote: > I'm able to reproduce random memory corruption after hibernate. > Corruption is not reproducible when I disable mode setting, what > seems to blame i915 driver or generic DRM kernel code. > > I'm able to reproduce bug on Fedora 11 with 2.6.30 kernel (first > fedora with KMS support) and on the latest 3.3-rc kernels. So this > issue is there from very beginning, hence it is not bisectable. > > I'm attaching script to reproduce (with accompanying memory checker > program). Script is basically sequence of hibernate - reset - check > memory. Kernel should be compiled with CONFIG_DEBUG_SLAB to detect > poison/redzone overwrites. > > I already tried to debug this using CONFIG_DEBUG_PAGEALLOC and new > kernel option debug_guardpage_minorder, but without any success. > Seems corruption happen behind CPU MMU, i.e. is DMA unit programming > bug. I'm not able to turn on IOMMU on that hardware. > > This happen on T500 laptop with, lspci output attached. > > I'm attaching also dmesg's with poison/redzone overwrites from > 3.3-rc4 and 2.6.30 kernels. > > Some more information can be found on: > https://bugzilla.redhat.com/show_bug.cgi?id=746169 > https://bugzilla.redhat.com/show_bug.cgi?id=701857 > > i.e there is invalid DMA address warning that could be a good hint: > https://bugzilla.redhat.com/show_bug.cgi?id=746169#c7 > > I would appreciate any help with solving this issue. I think many > people are hitting this, but since corruption happens at random, > not many people notice it, or when notice, did not find out that > this could be i915/DRM issue.
So, after googling a bit I find out that we are writing pixels into memory and issue is known since 2010 at least: http://codemonkey.org.uk/2012/03/12/i915-hibernate-memory-corruption/ https://bugzilla.novell.com/show_bug.cgi?id=697699 https://bugzilla.kernel.org/show_bug.cgi?id=13811 https://bugzilla.kernel.org/show_bug.cgi?id=37142 Keith, is there a chance that this bug can be fixed by i915 team? If not, can we disable hibernate on i915 with modeset=1 and add module option, which enable it for those who want to risk? Thanks Stanislaw
