From 8db7933ee3d442627c716ee49a70fa3aef18640d Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 24 Jun 2019 10:20:09 +0100 Subject: [PATCH] drm/i915/execlists: Always clear ring_pause if we do not submit In the unlikely case (thank you CI!), we may find ourselves wanting to issue a preemption but having no runnable requests left. In this case, we set the semaphore before computing the preemption and so must unset it before forgetting (or else we leave the machine busywaiting until the next request comes along and so likely hang). v2: Replace readback with only a wmb after asserting the semaphore Signed-off-by: Chris Wilson Cc: Mika Kuoppala Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20190624092009.30189-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/intel_lrc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index c8a0c9b32764..28685ba91a2c 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -240,7 +240,8 @@ ring_set_paused(const struct intel_engine_cs *engine, int state) * until the dword is false. */ engine->status_page.addr[I915_GEM_HWS_PREEMPT] = state; - wmb(); + if (state) + wmb(); } static inline struct i915_priolist *to_priolist(struct rb_node *rb) @@ -1243,6 +1244,8 @@ done: *port = execlists_schedule_in(last, port - execlists->pending); memset(port + 1, 0, (last_port - port) * sizeof(*port)); execlists_submit_ports(engine); + } else { + ring_set_paused(engine, 0); } } -- 2.30.2