From a20ab592d1a87218229109d109b8e2feae6f598d Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 21 Aug 2019 15:23:36 +0100
Subject: [PATCH] drm/i915/execlists: Set priority hint prior to submission
Git-commit: a20ab592d1a87218229109d109b8e2feae6f598d
Patch-mainline: v5.4-rc1
References: jsc#SLE-7953
Since we now run process_csb() outside of the engine->active.lock, we
can process a CS-event immediately upon our ELSP write. As we currently
inspect the pending queue *after* the ELSP write, there is an
opportunity for a CS-event to update the pending queue before we can
read it, making ourselves chases an invalid pointer.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111427
Fixes: df403069029d ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190821142336.21609-1-chris@chris-wilson.co.uk
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 44780e7fafec..d42584439f51 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1335,9 +1335,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
if (submit) {
*port = execlists_schedule_in(last, port - execlists->pending);
memset(port + 1, 0, (last_port - port) * sizeof(*port));
- execlists_submit_ports(engine);
execlists->switch_priority_hint =
switch_prio(engine, *execlists->pending);
+ execlists_submit_ports(engine);
} else {
ring_set_paused(engine, 0);
}
--
2.16.4