An oddity occurs on Sandybridge, Ivybridge and Haswell (and presumably Valleyview) in that for the period following the GPU restart after a reset, there are no GT interrupts received. From Ville's notes, bit 0 in the HWSTAM corresponds to the render interrupt, and if we unmask it we do see immediate resumption of GT interrupt delivery (via the master irq handler) after the reset. v2: Limit the w/a to the render interrupt from rcs Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107500 Fixes: c5498089463b ("drm/i915: Mask everything in ring HWSTAM on gen6+ in ringbuffer mode") References: d420a50c21ef ("drm/i915: Clean up the HWSTAM mess") Testcase: igt/gem_eio/reset-stress Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_ringbuffer.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 8003cef767ba..5a2601a4d1aa 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -387,8 +387,18 @@ static void intel_ring_setup_status_page(struct intel_engine_cs *engine) mmio = RING_HWS_PGA(engine->mmio_base); } - if (INTEL_GEN(dev_priv) >= 6) - I915_WRITE(RING_HWSTAM(engine->mmio_base), 0xffffffff); + if (INTEL_GEN(dev_priv) >= 6) { + u32 mask = ~0u; + + /* + * Keep the render interrupt unmasked as this papaers over + * lost interrupts following a reset. + */ + if (engine->id == RCS) + mask &= ~BIT(0); + + I915_WRITE(RING_HWSTAM(engine->mmio_base), mask); + } I915_WRITE(mmio, engine->status_page.ggtt_offset); POSTING_READ(mmio); -- 2.18.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
