Re: interference on display, Intel 945GM, 32bit system, kernel next

Chris Wilson
2015-07-31T14:54:38Z

On Fri, Jul 31, 2015 at 04:11:21PM +0200, Krzysztof Kolasa wrote:
> On 22.07.2015 10:27, Daniel Vetter wrote:
> > On Tue, Jul 21, 2015 at 08:07:47PM +0200, Krzysztof Kolasa wrote:
> >> On 21.07.2015 16:03, Daniel Vetter wrote:
> >>> On Tue, Jul 21, 2015 at 02:48:21PM +0200, Krzysztof Kolasa wrote:
> >>>> On 21.07.2015 11:43, Chris Wilson wrote:
> >>>>> On Tue, Jul 21, 2015 at 11:07:20AM +0200, Daniel Vetter wrote:
> >>>>>> On Tue, Jul 21, 2015 at 10:58:50AM +0200, Krzysztof Kolasa wrote:
> >>>>>>> On 21.07.2015 10:41, Daniel Vetter wrote:
> >>>>>>>> I meant whether you can reset the bad commit and it's immediate parent
> >>>>>>>> extensively to make sure the bisect is really correct. gpu's occasionally
> >>>>>>>> take a while to hang themselves, so could be that the bisect was
> >>>>>>>> mislead somewhere.
> >>>>>>> Again I will bisect, more testing good sections.
> >>>>>>>
> >>>>>>> At the moment on my old laptop, the latest official, properly working kernel is 4.1.2
> >>>>>> You don't need to redo the full bisect, only retest the bad and the parent
> >>>>>> of the bad extensively. That's enough to confirm the bisect result for
> >>>>>> sure.
> >>>>> The bisection is misleading. It's a missing write-barrier.
> >>>>> -Chris
> >>>>>
> >>>> tested again:
> >>>>
> >>>> # good: [cd102a687beed1042824d5fa81c6ba8bfe78e6a4] drm/i915: Remove misleading comment around bind_to_vm
> >>>> git bisect good cd102a687beed1042824d5fa81c6ba8bfe78e6a4
> >>>> # bad: [0875546c5318c85c13d07014af5350e9000bc9e9] drm/i915: Fix up the vma aliasing ppgtt binding
> >>>> git bisect bad 0875546c5318c85c13d07014af5350e9000bc9e9
> >>>> # first bad commit: [0875546c5318c85c13d07014af5350e9000bc9e9] drm/i915: Fix up the vma aliasing ppgtt binding
> >>>>
> >>>>
> >>>> Screen does not lie :) first bad is BAD, good is GOOD
> >>>>
> >>>> on commit cd102a687beed10, computer worked steadily (with a large number of windows, applications) about an hour and stopped the tests, everything was OK
> >>>>
> >>>> on commit 0875546c5318c85, after about one minute, the screen gone mad
> >>> Suprising. Can you try out the below patch, it should disable the active
> >>> ingredient of the offending. On older kernels just remove the if
> >>> (bind_flags) before the call to ->bind_vma - the point is to call
> >>> ->bind_vma unconditionally.
> >>> -Daniel
> >>>
> >>> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> >>> index cc133c700686..1227cd69c624 100644
> >>> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> >>> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> >>> @@ -2908,9 +2908,6 @@ int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
> >>> else
> >>> bind_flags &= ~vma->bound;
> >>>
> >>> - if (bind_flags == 0)
> >>> - return 0;
> >>> -
> >>> if (vma->bound == 0 && vma->vm->allocate_va_range) {
> >>> trace_i915_va_alloc(vma->vm,
> >>> vma->node.start,
> >>
> >> I tested the patch and did not help ...
> > Does this one below help?
> > -Daniel
> >
> > diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> > index d2df321ba634..38dce61e028d 100644
> > --- a/drivers/gpu/drm/i915/i915_dma.c
> > +++ b/drivers/gpu/drm/i915/i915_dma.c
> > @@ -150,9 +150,6 @@ static int i915_getparam(struct drm_device *dev, void *data,
> > case I915_PARAM_HAS_COHERENT_PHYS_GTT:
> > value = 1;
> > break;
> > - case I915_PARAM_MMAP_VERSION:
> > - value = 1;
> > - break;
> > case I915_PARAM_SUBSLICE_TOTAL:
> > value = INTEL_INFO(dev)->subslice_total;
> > if (!value)
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index 52b446b27b4d..c71525cefdf9 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -1676,7 +1676,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> > struct drm_gem_object *obj;
> > unsigned long addr;
> >
> > - if (args->flags & ~(I915_MMAP_WC))
> > + if (args->flags)
> > return -EINVAL;
> >
> > if (args->flags & I915_MMAP_WC && !cpu_has_pat)
> This commit solved the problem:
>
> http://cgit.freedesktop.org/drm-intel/commit/?id=d0e30adc42d979e4adc36b6c112b57337423b70c
>
> drm/i915: Mark PIN_USER binding as GLOBAL_BIND without the aliasing ppgtt

Oh well, still plenty of 4.0 victims to be worried about (which can't be
explained by the bug fixed by d0e30a).
-Chris

--
Chris Wilson, Intel Open Source Technology Centre