On pe, 2016-06-24 at 14:07 +0100, Chris Wilson wrote: > One of the numerous VT-d workarounds we require is that the display > hardware reads past the end of the buffer triggering VT-d faults. This > is acknowledged in the code as being safe "since we fill the unused > portions of the GGTT with the scratch page". Alas, that is no longer > always true and so we trigger DMAR read faults. > > Skylake also requires another workaround to avoid mixing VT-d and > unpopulated PTE, and so there we also need to ensure we fill unused > entries with the scratch page.
Rather agressive W/A for just scanout, so maybe drop the scanout word? > > Reported-by: Mike Lothian <m...@fireburn.co.uk> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96584 > Fixes: f7770bfd9fd2 ("drm/i915: Skip clearing the GGTT on full-ppgtt systems") > Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> > Cc: David Weinehall <david.weineh...@intel.com> > Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com> Reviewed-by: Joonas Lahtinen <joonas.lahti...@linux.intel.com> > --- > drivers/gpu/drm/i915/i915_drv.h | 9 +++++++++ > drivers/gpu/drm/i915/i915_gem_gtt.c | 2 +- > drivers/gpu/drm/i915/intel_display.c | 11 +---------- > 3 files changed, 11 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h > index 442386abd516..217ca3c9b1c6 100644 > --- a/drivers/gpu/drm/i915/i915_drv.h > +++ b/drivers/gpu/drm/i915/i915_drv.h > @@ -2857,6 +2857,15 @@ struct drm_i915_cmd_table { > > #include "i915_trace.h" > > +static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private > *dev_priv) > +{ > +#ifdef CONFIG_INTEL_IOMMU > + if (INTEL_GEN(dev_priv) >= 6 && intel_iommu_gfx_mapped) > + return true; > +#endif > + return false; > +} > + > extern int i915_suspend_switcheroo(struct drm_device *dev, pm_message_t > state); > extern int i915_resume_switcheroo(struct drm_device *dev); > > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c > b/drivers/gpu/drm/i915/i915_gem_gtt.c > index a8be1c2a8b9e..033fe10768e0 100644 > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c > @@ -2608,7 +2608,7 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt) > ggtt->base.unbind_vma = ggtt_unbind_vma; > ggtt->base.insert_page = gen8_ggtt_insert_page; > ggtt->base.clear_range = nop_clear_range; > - if (!USES_FULL_PPGTT(dev_priv)) > + if (!USES_FULL_PPGTT(dev_priv) || intel_scanout_needs_vtd_wa(dev_priv)) > ggtt->base.clear_range = gen8_ggtt_clear_range; > > ggtt->base.insert_entries = gen8_ggtt_insert_entries; > diff --git a/drivers/gpu/drm/i915/intel_display.c > b/drivers/gpu/drm/i915/intel_display.c > index a8b0ec13dfe9..8145b65c4262 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -2071,15 +2071,6 @@ static void intel_disable_pipe(struct intel_crtc *crtc) > intel_wait_for_pipe_off(crtc); > } > > -static bool need_vtd_wa(struct drm_device *dev) > -{ > -#ifdef CONFIG_INTEL_IOMMU > - if (INTEL_INFO(dev)->gen >= 6 && intel_iommu_gfx_mapped) > - return true; > -#endif > - return false; > -} > - > static unsigned int intel_tile_size(const struct drm_i915_private *dev_priv) > { > return IS_GEN2(dev_priv) ? 2048 : 4096; > @@ -2262,7 +2253,7 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, > unsigned int rotation) > * we should always have valid PTE following the scanout preventing > * the VT-d warning. > */ > - if (need_vtd_wa(dev) && alignment < 256 * 1024) > + if (intel_scanout_needs_vtd_wa(dev_priv) && alignment < 256 * 1024) > alignment = 256 * 1024; > > /* -- Joonas Lahtinen Open Source Technology Center Intel Corporation _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
