On Thu, Jan 09, 2014 at 10:58:35AM +0100, Daniel Vetter wrote: > On Thu, Jan 09, 2014 at 09:45:21AM +0000, Chris Wilson wrote: > > On Thu, Jan 09, 2014 at 11:00:17AM +0530, akash.goel@xxxxxxxxx wrote: > > > From: Akash Goel <akash.goel@xxxxxxxxx> > > > > > > The 'offset' field of the 'scatterlist' structure was wrongly > > > programmed with the offset value from the base of stolen area, > > > whereas this field indicates the offset from where the interested > > > data starts within the PAGE pointed to by the 'page-link' field. > > > As a result when a new GEM object allocated from the stolen > > > area is mapped to GTT, it could lead to an overwrite of GTT entries > > > as the page count calculation will go wrong, refer the function > > > 'sg_page_count'. > > > > This statement is incorrect since my use of sg here predates > > sg_page_iter. > > > > The stolen sg has no page_link, the meaning of offset/length here are > > relative to the base of the stolen area. > > > > However, if you wish to rephrase the above... > > Actually we add offset both to sg->offset and adjust the dma_bus_addr > since this has been introduced in > > commit 0104fdbb84d7adb0e377ed05bf75eba97b007544 > Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Date: Thu Nov 15 11:32:26 2012 +0000 > > drm/i915: Introduce i915_gem_object_create_stolen() > > But only Imre's conversion to the sg_page_iter started to pay any > attention to sg->offset in > > commit 6e995e231a90ce7c5ce2a9eae23c8e22f4388db1 > Author: Imre Deak <imre.deak@xxxxxxxxx> > Date: Mon Feb 18 19:28:04 2013 +0200 > > drm/i915: use for_each_sg_page for setting up the gtt ptes > > So with a bit of commit message rewording and these references and cc: > stable this looks good. And Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69104 Tested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Maybe a reviewed-by when I see a good comment/changelog. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
