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authorBen Skeggs <bskeggs@redhat.com>2017-05-11 17:13:29 +1000
committerBen Skeggs <bskeggs@redhat.com>2017-05-12 08:32:58 +1000
commit330bdf62fe6a6c5b99a647f7bf7157107c9348b3 (patch)
tree1fe7a3da274d6a66fd77d4326704b9232fa3a07c
parent9fc64667ee48c9a25e7dca1a6bcb6906fec5bcc5 (diff)
downloadlinux-stericsson-330bdf62fe6a6c5b99a647f7bf7157107c9348b3.tar.gz
drm/nouveau/tmr: avoid processing completed alarms when adding a new one
The idea here was to avoid having to "manually" program the HW if there's a new earliest alarm. This was lazy and bad, as it leads to loads of fun races between inter-related callers (ie. therm). Turns out, it's not so difficult after all. Go figure ;) Signed-off-by: Ben Skeggs <bskeggs@redhat.com> Cc: stable@vger.kernel.org
-rw-r--r--drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c
index d898787d514c..f2a86eae0a0d 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c
@@ -86,12 +86,22 @@ nvkm_timer_alarm(struct nvkm_timer *tmr, u32 nsec, struct nvkm_alarm *alarm)
if (list->timestamp > alarm->timestamp)
break;
}
+
list_add_tail(&alarm->head, &list->head);
+
+ /* Update HW if this is now the earliest alarm. */
+ list = list_first_entry(&tmr->alarms, typeof(*list), head);
+ if (list == alarm) {
+ tmr->func->alarm_init(tmr, alarm->timestamp);
+ /* This shouldn't happen if callers aren't stupid.
+ *
+ * Worst case scenario is that it'll take roughly
+ * 4 seconds for the next alarm to trigger.
+ */
+ WARN_ON(alarm->timestamp <= nvkm_timer_read(tmr));
+ }
}
spin_unlock_irqrestore(&tmr->lock, flags);
-
- /* process pending alarms */
- nvkm_timer_alarm_trigger(tmr);
}
void