From 2e8f9d322948406fb3aa0b27bda4d40a34e57123 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 16 Mar 2017 17:13:04 +0000 Subject: [PATCH] drm/i915: Restore engine->submit_request before unwedging When we wedge the device, we override engine->submit_request with a nop to ensure that all in-flight requests are marked in error. However, igt would like to unwedge the device to test -EIO handling. This requires us to flush those in-flight requests and restore the original engine->submit_request. v2: Use a vfunc to unify enabling request submission to engines v3: Split new vfunc to a separate patch. v4: Make the wait interruptible -- the third party fences we wait upon may be indefinitely broken, so allow the reset to be aborted. Fixes: 821ed7df6e2a ("drm/i915: Update reset path to fix incomplete requests") Testcase: igt/gem_eio Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Mika Kuoppala Reviewed-by: Tvrtko Ursulin #v3 Link: http://patchwork.freedesktop.org/patch/msgid/20170316171305.12972-3-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_drv.c | 9 ++++--- drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/i915_gem.c | 59 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 66 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index be3c812..03d9e45 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -1821,7 +1821,9 @@ void i915_reset(struct drm_i915_private *dev_priv) return; /* Clear any previous failed attempts at recovery. Time to try again. */ - __clear_bit(I915_WEDGED, &error->flags); + if (!i915_gem_unset_wedged(dev_priv)) + goto wakeup; + error->reset_count++; pr_notice("drm/i915: Resetting chip after gpu hang\n"); @@ -1867,17 +1869,18 @@ void i915_reset(struct drm_i915_private *dev_priv) i915_queue_hangcheck(dev_priv); -wakeup: +finish: i915_gem_reset_finish(dev_priv); enable_irq(dev_priv->drm.irq); +wakeup: clear_bit(I915_RESET_HANDOFF, &error->flags); wake_up_bit(&error->flags, I915_RESET_HANDOFF); return; error: i915_gem_set_wedged(dev_priv); - goto wakeup; + goto finish; } static int i915_pm_suspend(struct device *kdev) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index fcc8184..2f28d3c 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -3441,6 +3441,7 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv); void i915_gem_reset(struct drm_i915_private *dev_priv); void i915_gem_reset_finish(struct drm_i915_private *dev_priv); void i915_gem_set_wedged(struct drm_i915_private *dev_priv); +bool i915_gem_unset_wedged(struct drm_i915_private *dev_priv); void i915_gem_init_mmio(struct drm_i915_private *i915); int __must_check i915_gem_init(struct drm_i915_private *dev_priv); diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index ecd1b03..fd611b4 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2997,6 +2997,65 @@ void i915_gem_set_wedged(struct drm_i915_private *dev_priv) mod_delayed_work(dev_priv->wq, &dev_priv->gt.idle_work, 0); } +bool i915_gem_unset_wedged(struct drm_i915_private *i915) +{ + struct i915_gem_timeline *tl; + int i; + + lockdep_assert_held(&i915->drm.struct_mutex); + if (!test_bit(I915_WEDGED, &i915->gpu_error.flags)) + return true; + + /* Before unwedging, make sure that all pending operations + * are flushed and errored out - we may have requests waiting upon + * third party fences. We marked all inflight requests as EIO, and + * every execbuf since returned EIO, for consistency we want all + * the currently pending requests to also be marked as EIO, which + * is done inside our nop_submit_request - and so we must wait. + * + * No more can be submitted until we reset the wedged bit. + */ + list_for_each_entry(tl, &i915->gt.timelines, link) { + for (i = 0; i < ARRAY_SIZE(tl->engine); i++) { + struct drm_i915_gem_request *rq; + + rq = i915_gem_active_peek(&tl->engine[i].last_request, + &i915->drm.struct_mutex); + if (!rq) + continue; + + /* We can't use our normal waiter as we want to + * avoid recursively trying to handle the current + * reset. The basic dma_fence_default_wait() installs + * a callback for dma_fence_signal(), which is + * triggered by our nop handler (indirectly, the + * callback enables the signaler thread which is + * woken by the nop_submit_request() advancing the seqno + * and when the seqno passes the fence, the signaler + * then signals the fence waking us up). + */ + if (dma_fence_default_wait(&rq->fence, true, + MAX_SCHEDULE_TIMEOUT) < 0) + return false; + } + } + + /* Undo nop_submit_request. We prevent all new i915 requests from + * being queued (by disallowing execbuf whilst wedged) so having + * waited for all active requests above, we know the system is idle + * and do not have to worry about a thread being inside + * engine->submit_request() as we swap over. So unlike installing + * the nop_submit_request on reset, we can do this from normal + * context and do not require stop_machine(). + */ + intel_engines_reset_default_submission(i915); + + smp_mb__before_atomic(); /* complete takeover before enabling execbuf */ + clear_bit(I915_WEDGED, &i915->gpu_error.flags); + + return true; +} + static void i915_gem_retire_work_handler(struct work_struct *work) { -- 2.7.4