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

Daniel Vetter
2015-07-22T08:24:38Z

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)
--
Daniel Vetter
Software Engineer, Intel Corporation