In the next patch, we will make the execlists reset prepare callback take into account preemption by flushing the context-switch handler. This is not applicable to the GuC submission backend, so split the two into their own backend callbacks.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> Cc: MichaĆ Winiarski <michal.winiar...@intel.com> CC: Michel Thierry <michel.thie...@intel.com> Cc: Jeff McGee <jeff.mc...@intel.com> --- drivers/gpu/drm/i915/intel_guc_submission.c | 39 +++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_lrc.c | 11 +------- 2 files changed, 40 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c index 207cda062626..779c8d3156e5 100644 --- a/drivers/gpu/drm/i915/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/intel_guc_submission.c @@ -776,6 +776,44 @@ static void guc_submission_tasklet(unsigned long data) guc_dequeue(engine); } +static struct i915_request * +guc_reset_prepare(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + + /* + * Prevent request submission to the hardware until we have + * completed the reset in i915_gem_reset_finish(). If a request + * is completed by one engine, it may then queue a request + * to a second via its execlists->tasklet *just* as we are + * calling engine->init_hw() and also writing the ELSP. + * Turning off the execlists->tasklet until the reset is over + * prevents the race. + * + * Note that this needs to be a single atomic operation on the + * tasklet (flush existing tasks, prevent new tasks) to prevent + * a race between reset and set-wedged. It is not, so we do the best + * we can atm and make sure we don't lock the machine up in the more + * common case of recursively being called from set-wedged from inside + * i915_reset. + */ + if (!atomic_read(&execlists->tasklet.count)) + tasklet_kill(&execlists->tasklet); + tasklet_disable(&execlists->tasklet); + + /* + * We're using worker to queue preemption requests from the tasklet in + * GuC submission mode. + * Even though tasklet was disabled, we may still have a worker queued. + * Let's make sure that all workers scheduled before disabling the + * tasklet are completed before continuing with the reset. + */ + if (engine->i915->guc.preempt_wq) + flush_workqueue(engine->i915->guc.preempt_wq); + + return i915_gem_find_active_request(engine); +} + /* * Everything below here is concerned with setup & teardown, and is * therefore not part of the somewhat time-critical batch-submission @@ -1235,6 +1273,7 @@ int intel_guc_submission_enable(struct intel_guc *guc) &engine->execlists; execlists->tasklet.func = guc_submission_tasklet; + engine->reset.prepare = guc_reset_prepare; engine->park = guc_submission_park; engine->unpark = guc_submission_unpark; diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index f662a9524233..e5a3ffbc273a 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1688,16 +1688,6 @@ execlists_reset_prepare(struct intel_engine_cs *engine) tasklet_kill(&execlists->tasklet); tasklet_disable(&execlists->tasklet); - /* - * We're using worker to queue preemption requests from the tasklet in - * GuC submission mode. - * Even though tasklet was disabled, we may still have a worker queued. - * Let's make sure that all workers scheduled before disabling the - * tasklet are completed before continuing with the reset. - */ - if (engine->i915->guc.preempt_wq) - flush_workqueue(engine->i915->guc.preempt_wq); - return i915_gem_find_active_request(engine); } @@ -2115,6 +2105,7 @@ static void execlists_set_default_submission(struct intel_engine_cs *engine) engine->cancel_requests = execlists_cancel_requests; engine->schedule = execlists_schedule; engine->execlists.tasklet.func = execlists_submission_tasklet; + engine->reset.prepare = execlists_reset_prepare; engine->park = NULL; engine->unpark = NULL; -- 2.16.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx