Quoting Tvrtko Ursulin (2020-04-27 10:50:01) > > On 27/04/2020 09:40, Chris Wilson wrote: > > We see that if the HW doesn't actually sleep, the HW may eat the poison > > we set in its write-only HWSP during sanitize: > > > > intel_gt_resume.part.8: 0000:00:02.0 > > __gt_unpark: 0000:00:02.0 > > gt_sanitize: 0000:00:02.0 force:yes > > process_csb: 0000:00:02.0 vcs0: cs-irq head=5, tail=90 > > process_csb: 0000:00:02.0 vcs0: csb[0]: status=0x5a5a5a5a:0x5a5a5a5a > > assert_pending_valid: Nothing pending for promotion! > > > > The CS TAIL pointer should have been reset by reset_csb_pointers(), so > > in this case it is likely that we have read back from the CPU cache and > > so we must clflush our control over that page. In doing so, push the > > sanitisation to the start of the GT sequence so that our poisoning is > > assuredly before we start talking to the HW. > > > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/i915/gt/intel_gt_pm.c | 3 ++- > > drivers/gpu/drm/i915/gt/intel_lrc.c | 3 +++ > > 2 files changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c > > index 4c4c74ef4f21..5097786f4375 100644 > > --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c > > +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c > > @@ -198,11 +198,12 @@ int intel_gt_resume(struct intel_gt *gt) > > * Only the kernel contexts should remain pinned over suspend, > > * allowing us to fixup the user contexts on their first pin. > > */ > > + gt_sanitize(gt, true); > > + > > intel_gt_pm_get(gt); > > gt_sanitize declares hw access so I thin it should still be after this > pm get. We control the rpm/uncore access inside gt_sanitize. And the reset we do there avoid interfering with the gt_pm, so I think this is safe. Note that the gt_sanitize() we do later is after we release gt_pm. So it seems reasonable to say that we do it before/after gt_pm. _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
