Re: question about i915 driver in dom0

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

> > > I hadn't seen it... but then my main desktop box where I run intensive
> > > tests (ie, games) is radeon and nvidia so hadn't really tried seen this.
> > > The box that has i915 just does some simple framebuffer manipulation and
> > > that looks OK.
> > 
> > yes, framebuffer console works well in my side too.

Good.
> > > Do you see the same symptoms - checkboard screen?
> > 
> > Not exactly. The screen becomes white, and then the system becomes
> > unstable and hang several minutes later. It's possible that mine is a
> > different issue than listed on the wiki page, since many reasons may
> > finally reach the same symptom - GPU hang... :/
> 
> well, there happens once with a checkboard screen, with the rest all
> white screens.
> 
> > 
> > >
> > > The LKML had some fixes for this from Keith Packard. Something about
> > > using i915.semaphores=0 I think. And I thought I saw some fixes for
> > > 3.2-rc7 for this but not sure..
> > 
> > I'll have a try on latest Linux on this. But I suspect that this may be a
> > virtualization specific bug (e.g. similar gfn/mfn issue as nvidia case),
> > because same dom0 image could run glxgear smoothly on bare metal.
> > 
> 
> I used latest 3.2 release, no difference.

What is the motherboard you have? I just bought an "DQ67SW" which perhaps
has the same video card?


But more interestingly - are you building your kernel from scratch? There
was some requirements in having CONFIG_IOMMU_DMAR in the kernels - otherwise
the intel-gtt.c would use the 'virt_to_phys' code instead of the DMA API.

And that caused an endless amount of pain.
> 
> i915.semaphores=0 has no effect.
> 
> But I observed below warnings in the boot process:
> [    8.872430] [drm] MTRR allocation failed.  Graphics performance may suffer.
> [   18.384552] microcode: CPU0 update to revision 0x1b failed
> 
> Not sure whether above two issues may have impact on the said problem. 
> I know microcode update is still missing in upstream, but not sure about any

Right, microcode is ... pending hpa's coming back from paternity leave.
> MTRR specific pending patches.

The MTRR are not in, but the graphics code should still work.