From: Ben Skeggs Date: Thu, 11 May 2017 07:13:29 +0000 (+1000) Subject: drm/nouveau/tmr: avoid processing completed alarms when adding a new one X-Git-Tag: release-20171130_firefly~4^2~100^2~1^2~7^2~68 X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=9d78e40f5f41ad1db1849f8d15acbda99d0871b4;p=firefly-linux-kernel-4.4.55.git drm/nouveau/tmr: avoid processing completed alarms when adding a new one commit 330bdf62fe6a6c5b99a647f7bf7157107c9348b3 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c index 4e958db23ca0..74e40f1d8f52 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c @@ -80,12 +80,22 @@ 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