From d41a3c2be178783c85e05025265ab58fbb4d4ce1 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 7 Aug 2017 13:19:19 +0100 Subject: [PATCH] drm/i915: Clear lost context-switch interrupts across reset Git-commit: d41a3c2be178783c85e05025265ab58fbb4d4ce1 Patch-mainline: v4.13-rc7 References: FATE#322643 bsc#1055900 No-fix: 64f09f00caf0a7cb40a8c0b85789bacba0f51d9e During a global reset, we disable the irq. As we disable the irq, the hardware may be raising a GT interrupt that we then ignore, leaving it pending in the GTIIR. After the reset, we then re-enable the irq, triggering the pending interrupt. However, that interrupt was for the stale state from before the reset, and the contents of the CSB buffer are now invalid. V2: Add a comment to make it clear that the double clear is purely my paranoia. Reported-by: "Dong, Chuanxiao" Fixes: 821ed7df6e2a ("drm/i915: Update reset path to fix incomplete requests") Signed-off-by: Chris Wilson Cc: "Dong, Chuanxiao" Cc: Tvrtko Ursulin Cc: Michal Winiarski Cc: Michel Thierry Link: https://patchwork.freedesktop.org/patch/msgid/20170807121919.30165-1-chris@chris-wilson.co.uk Link: https://patchwork.freedesktop.org/patch/msgid/20170818090509.5363-1-chris@chris-wilson.co.uk Reviewed-by: Michel Thierry (cherry picked from commit 64f09f00caf0a7cb40a8c0b85789bacba0f51d9e) Signed-off-by: Jani Nikula Acked-by: Takashi Iwai --- drivers/gpu/drm/i915/intel_lrc.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1221,6 +1221,14 @@ static int intel_init_workaround_bb(stru return ret; } +static u8 gtiir[] = { + [RCS] = 0, + [BCS] = 0, + [VCS] = 1, + [VCS2] = 1, + [VECS] = 3, +}; + static int gen8_init_common_ring(struct intel_engine_cs *engine) { struct drm_i915_private *dev_priv = engine->i915; @@ -1245,9 +1253,22 @@ static int gen8_init_common_ring(struct DRM_DEBUG_DRIVER("Execlists enabled for %s\n", engine->name); - /* After a GPU reset, we may have requests to replay */ + GEM_BUG_ON(engine->id >= ARRAY_SIZE(gtiir)); + + /* + * Clear any pending interrupt state. + * + * We do it twice out of paranoia that some of the IIR are double + * buffered, and if we only reset it once there may still be + * an interrupt pending. + */ + I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]), + GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift); + I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]), + GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift); clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted); + /* After a GPU reset, we may have requests to replay */ submit = false; for (n = 0; n < ARRAY_SIZE(engine->execlist_port); n++) { if (!port_isset(&port[n]))