On Wed, Dec 10, 2014 at 11:13:28AM +0000, Chris Wilson wrote: > On Wed, Dec 10, 2014 at 11:23:44AM +0100, Daniel Vetter wrote: > > On Wed, Dec 10, 2014 at 08:17:11AM +0000, Chris Wilson wrote: > > > This added as a BUG_ON as it considered that no one would ever request > > > an unaligned object. However, it turns out that some BIOSes will > > > allocate a scanout that is offset from 0 and not aligned to a page > > > boundary, and we were passing this through and hitting the BUG_ON during > > > boot. > > > > > > Quietly reject such a request to reserve the unaligned stolen object and > > > let the boot continue, restoring previous behaviour (i.e. no BIOS > > > framebuffer preservation). > > > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86883 > > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > > Cc: stable@xxxxxxxxxxxxxxx > > > --- > > > drivers/gpu/drm/i915/i915_gem_stolen.c | 10 ++++++---- > > > 1 file changed, 6 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c > > > index 5c616ec2c5c8..a3bc0fa07c6c 100644 > > > --- a/drivers/gpu/drm/i915/i915_gem_stolen.c > > > +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c > > > @@ -646,13 +646,15 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev, > > > DRM_DEBUG_KMS("creating preallocated stolen object: stolen_offset=%x, gtt_offset=%x, size=%x\n", > > > stolen_offset, gtt_offset, size); > > > > > > - /* KISS and expect everything to be page-aligned */ > > > - BUG_ON(stolen_offset & 4095); > > > - BUG_ON(size & 4095); > > > - > > > if (WARN_ON(size == 0)) > > > return NULL; > > > > > > + /* KISS and expect everything to be GTT page-aligned */ > > > + if ((stolen_offset | size) & 4095) { > > > > Imo we should stil WARN_ON and fixup up the takeover code to align things > > properly ... > > You shot down my idea for storing deltas into objects in the past... > > The BIOS scanout is properly aligned to the rules of the display engine, > just not according to our mm restrictions. The bigger question is > whether our 1:1 offset-to-stolen mapping is correct. It could well be > that that the framebuffer is at stolen address 0, but just has a GTT > offset. > > So the only question is whether we reject the object reservation at the > stolen layer or at the plane config layer. I decided that stolen was > better, because it is failing to meet our mm restrictions not > hardware restrictions. The framebuffer layer can very much cope with offsets, so no need to reject it. We just need to patch up the framebuffer we create a bit. Offsets are in pixels but that should align well. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html