From 3f6e9822308127104a7bb007ca569f2c57d03b67 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 16 May 2018 19:33:55 +0100 Subject: [PATCH] drm/i915: Stop parking the signaler around reset MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit We cannot call kthread_park() from softirq context, so let's avoid it entirely during the reset. We wanted to suspend the signaler so that it would not mark a request as complete at the same time as we marked it as being in error. Instead of parking the signaling, stop the engine from advancing so that the GPU doesn't emit the breadcrumb for our chosen "guilty" request. v2: Refactor setting STOP_RING so that we don't have the same code thrice Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Michałt Winiarski CC: Michel Thierry Cc: Jeff McGee Cc: Tvrtko Ursulin Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20180516183355.10553-8-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem.c | 14 -------------- drivers/gpu/drm/i915/intel_engine_cs.c | 29 +++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_lrc.c | 6 ++++++ drivers/gpu/drm/i915/intel_ringbuffer.c | 2 ++ drivers/gpu/drm/i915/intel_ringbuffer.h | 2 ++ drivers/gpu/drm/i915/intel_uncore.c | 12 +++--------- 6 files changed, 42 insertions(+), 23 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index abf661d..b0fe452 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -3015,18 +3015,6 @@ i915_gem_reset_prepare_engine(struct intel_engine_cs *engine) */ intel_uncore_forcewake_get(engine->i915, FORCEWAKE_ALL); - /* - * Prevent the signaler thread from updating the request - * state (by calling dma_fence_signal) as we are processing - * the reset. The write from the GPU of the seqno is - * asynchronous and the signaler thread may see a different - * value to us and declare the request complete, even though - * the reset routine have picked that request as the active - * (incomplete) request. This conflict is not handled - * gracefully! - */ - kthread_park(engine->breadcrumbs.signaler); - request = engine->reset.prepare(engine); if (request && request->fence.error == -EIO) request = ERR_PTR(-EIO); /* Previous reset failed! */ @@ -3229,8 +3217,6 @@ void i915_gem_reset_finish_engine(struct intel_engine_cs *engine) { engine->reset.finish(engine); - kthread_unpark(engine->breadcrumbs.signaler); - intel_uncore_forcewake_put(engine->i915, FORCEWAKE_ALL); } diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index 6bfd7e3..d4e159a 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -769,6 +769,35 @@ u64 intel_engine_get_last_batch_head(const struct intel_engine_cs *engine) return bbaddr; } +int intel_engine_stop_cs(struct intel_engine_cs *engine) +{ + struct drm_i915_private *dev_priv = engine->i915; + const u32 base = engine->mmio_base; + const i915_reg_t mode = RING_MI_MODE(base); + int err; + + if (INTEL_GEN(dev_priv) < 3) + return -ENODEV; + + GEM_TRACE("%s\n", engine->name); + + I915_WRITE_FW(mode, _MASKED_BIT_ENABLE(STOP_RING)); + + err = 0; + if (__intel_wait_for_register_fw(dev_priv, + mode, MODE_IDLE, MODE_IDLE, + 1000, 0, + NULL)) { + GEM_TRACE("%s: timed out on STOP_RING -> IDLE\n", engine->name); + err = -ETIMEDOUT; + } + + /* A final mmio read to let GPU writes be hopefully flushed to memory */ + POSTING_READ_FW(mode); + + return err; +} + const char *i915_cache_level_str(struct drm_i915_private *i915, int type) { switch (type) { diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index a83273c..493e6bd 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1879,6 +1879,12 @@ execlists_reset_prepare(struct intel_engine_cs *engine) if (request) { unsigned long flags; + /* + * Prevent the breadcrumb from advancing before we decide + * which request is currently active. + */ + intel_engine_stop_cs(engine); + spin_lock_irqsave(&engine->timeline.lock, flags); list_for_each_entry_from_reverse(request, &engine->timeline.requests, diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index af5a178..6f200a7 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -533,6 +533,8 @@ out: static struct i915_request *reset_prepare(struct intel_engine_cs *engine) { + intel_engine_stop_cs(engine); + if (engine->irq_seqno_barrier) engine->irq_seqno_barrier(engine); diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index 1e8bacb..61f385a 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -878,6 +878,8 @@ int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine); int intel_init_blt_ring_buffer(struct intel_engine_cs *engine); int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine); +int intel_engine_stop_cs(struct intel_engine_cs *engine); + u64 intel_engine_get_active_head(const struct intel_engine_cs *engine); u64 intel_engine_get_last_batch_head(const struct intel_engine_cs *engine); diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 448293e..b36a3b5 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1702,15 +1702,9 @@ static void gen3_stop_engine(struct intel_engine_cs *engine) { struct drm_i915_private *dev_priv = engine->i915; const u32 base = engine->mmio_base; - const i915_reg_t mode = RING_MI_MODE(base); - - I915_WRITE_FW(mode, _MASKED_BIT_ENABLE(STOP_RING)); - if (__intel_wait_for_register_fw(dev_priv, - mode, MODE_IDLE, MODE_IDLE, - 500, 0, - NULL)) - DRM_DEBUG_DRIVER("%s: timed out on STOP_RING\n", - engine->name); + + if (intel_engine_stop_cs(engine)) + DRM_DEBUG_DRIVER("%s: timed out on STOP_RING\n", engine->name); I915_WRITE_FW(RING_HEAD(base), I915_READ_FW(RING_TAIL(base))); POSTING_READ_FW(RING_HEAD(base)); /* paranoia */ -- 2.7.4