On Wed, Nov 11, 2015 at 2:37 PM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > On Tue, Nov 10, 2015 at 03:27:36PM -0800, yu.dai@xxxxxxxxx wrote: >> From: Alex Dai <yu.dai@xxxxxxxxx> >> >> We keep a copy of GuC fw in a GEM obj. However its content is lost >> if the GEM obj is swapped (igt/gem_evict_*). Therefore, the later >> fw loading during GPU reset will fail. Mark the obj dirty after >> copying data into the pages. So its content will be kept during >> swapped out. >> >> Signed-off-by: Alex Dai <yu.dai@xxxxxxxxx> >> --- >> drivers/gpu/drm/i915/i915_gem.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c >> index f1e3fde..3b15167 100644 >> --- a/drivers/gpu/drm/i915/i915_gem.c >> +++ b/drivers/gpu/drm/i915/i915_gem.c >> @@ -5199,6 +5199,7 @@ i915_gem_object_create_from_data(struct drm_device *dev, >> i915_gem_object_pin_pages(obj); >> sg = obj->pages; >> bytes = sg_copy_from_buffer(sg->sgl, sg->nents, (void *)data, size); >> + obj->dirty = 1; > > That's one way of doing it, but atypical for our CPU access to the pages. > The root cause is still that sg_copy_from_buffer() isn't calling > set_page_dirty() and so there will be other places in the kernel that > fall foul of it. Also, not that we could have written this to not require > the whole object to be pinned at once as well. > > I would prefer this to be fixed in sg_copy_from_buffer() for the reason > that all callers are susceptible to this bug. > -Chris Probably the sg_copy_from_buffer is written with an assumption that the pages it is supposed to write to, would always be the kernel pages (GFP_KERNEL), which will always be resident in RAM. Thus no real need to mark the pages as dirty. Or the Clients/Users of sg_copy_from_buffer function are expected to explicitly mark the pages as dirty. Best regards Akash > > -- > Chris Wilson, Intel Open Source Technology Centre > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
