From 0364cd19d61caad7292cc4e87f5001595b6c7642 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 21 Jul 2017 13:32:21 +0100 Subject: [PATCH] drm/i915: Serialize per-engine resets against new requests We rely on disabling the execlists (by stopping the tasklet) to prevent new requests from submitting to the engine ELSP before we are ready. However, we re-enable the engine before we call init_hw which gives userspace the opportunity to subit a new request which is then overwritten by init_hw -- but not before the HW may have started executing. The subsequent out-of-order CSB is detected by our sanity checks in intel_lrc_irq_handler(). Fixes: a1ef70e14453 ("drm/i915: Add support for per engine reset recovery") Signed-off-by: Chris Wilson Cc: Michel Thierry Cc: Mika Kuoppala Reviewed-by: Michel Thierry Link: https://patchwork.freedesktop.org/patch/msgid/20170721123238.16428-3-chris@chris-wilson.co.uk Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 853d674..6753fc8 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -1951,6 +1951,12 @@ int i915_reset_engine(struct intel_engine_cs *engine) } ret = intel_gpu_reset(engine->i915, intel_engine_flag(engine)); + if (ret) { + /* If we fail here, we expect to fallback to a global reset */ + DRM_DEBUG_DRIVER("Failed to reset %s, ret=%d\n", + engine->name, ret); + goto out; + } /* * The request that caused the hang is stuck on elsp, we know the @@ -1959,15 +1965,6 @@ int i915_reset_engine(struct intel_engine_cs *engine) */ i915_gem_reset_engine(engine, active_request); - i915_gem_reset_finish_engine(engine); - - if (ret) { - /* If we fail here, we expect to fallback to a global reset */ - DRM_DEBUG_DRIVER("Failed to reset %s, ret=%d\n", - engine->name, ret); - goto out; - } - /* * The engine and its registers (and workarounds in case of render) * have been reset to their default values. Follow the init_ring @@ -1979,6 +1976,7 @@ int i915_reset_engine(struct intel_engine_cs *engine) error->reset_engine_count[engine->id]++; out: + i915_gem_reset_finish_engine(engine); return ret; } -- 2.7.4