On Mon, 26 Nov 2012 21:52:54 -0800 Ben Widawsky <[email protected]> wrote:
> This bug was introduced by me: > commit e76e9aebcdbfebae8f4cd147e3c0f800d36e97f3 > Author: Ben Widawsky <[email protected]> > Date: Sun Nov 4 09:21:27 2012 -0800 > > drm/i915: Stop using AGP layer for GEN6+ > > The existing code uses memset_io which follows memset semantics in only > guaranteeing a write of individual bytes. Since a PTE entry is 4 bytes, > this can only be correct if the scratch page address is 0. > > This caused unsightly errors when we clear the range at load time, > though I'm not really sure what the heck is referencing that memory > anyway. I caught this is because I believe we have some other bug where > the display is doing reads of memory we feel should be cleared (or we > are relying on scratch pages to be a specific value). > > Signed-off-by: Ben Widawsky <[email protected]> > --- > drivers/gpu/drm/i915/i915_gem_gtt.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c > b/drivers/gpu/drm/i915/i915_gem_gtt.c > index 51f79bb..f7ac61e 100644 > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c > @@ -367,8 +367,9 @@ static void i915_ggtt_clear_range(struct drm_device *dev, > { > struct drm_i915_private *dev_priv = dev->dev_private; > gtt_pte_t scratch_pte; > - volatile void __iomem *gtt_base = dev_priv->mm.gtt->gtt + first_entry; > + gtt_pte_t __iomem *gtt_base = dev_priv->mm.gtt->gtt + first_entry; > const int max_entries = dev_priv->mm.gtt->gtt_total_entries - > first_entry; > + int i; > > if (INTEL_INFO(dev)->gen < 6) { > intel_gtt_clear_range(first_entry, num_entries); > @@ -381,7 +382,8 @@ static void i915_ggtt_clear_range(struct drm_device *dev, > num_entries = max_entries; > > scratch_pte = pte_encode(dev, dev_priv->mm.gtt->scratch_page_dma, > I915_CACHE_LLC); > - memset_io(gtt_base, scratch_pte, num_entries * sizeof(scratch_pte)); > + for (i = 0; i < num_entries; i++) > + iowrite32(scratch_pte, >t_base[i]); > readl(gtt_base); > } > "This has been slurped into -queued. Thanks for the patch" - or something like that. -- Ben Widawsky, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
