While we only allow a single display power reference, the current
acquisition/release is racy and a direct call may run concurrently with
a runtime-pm worker. Prevent the double unreference by atomically
tracking the display_power_active cookie.
Testcase: igt/i915_pm_rpm/module-reload #glk-dsi
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxx>
Cc: Imre Deak <imre.deak@xxxxxxxxx>
---
sound/hda/hdac_component.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/sound/hda/hdac_component.c b/sound/hda/hdac_component.c
index 13915fdc6a54..f0fd0d83c90e 100644
--- a/sound/hda/hdac_component.c
+++ b/sound/hda/hdac_component.c
@@ -66,6 +66,7 @@ EXPORT_SYMBOL_GPL(snd_hdac_set_codec_wakeup);
void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx, bool enable)
{
struct drm_audio_component *acomp = bus->audio_component;
+ unsigned long cookie;
dev_dbg(bus->dev, "display power %s\n",
enable ? "enable" : "disable");
@@ -78,26 +79,22 @@ void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx, bool enable)
return;
if (bus->display_power_status) {
- if (!bus->display_power_active) {
- unsigned long cookie = -1;
-
- if (acomp->ops->get_power)
- cookie = acomp->ops->get_power(acomp->dev);
+ cookie = -1;
+ if (acomp->ops->get_power)
+ cookie = acomp->ops->get_power(acomp->dev);
+ if (!cmpxchg(&bus->display_power_active, 0, cookie)) {
snd_hdac_set_codec_wakeup(bus, true);
snd_hdac_set_codec_wakeup(bus, false);
- bus->display_power_active = cookie;
+ cookie = 0;
}
} else {
- if (bus->display_power_active) {
- unsigned long cookie = bus->display_power_active;
+ cookie = xchg(&bus->display_power_active, 0);
+ }
- if (acomp->ops->put_power)
- acomp->ops->put_power(acomp->dev, cookie);
+ if (cookie && acomp->ops->put_power)
+ acomp->ops->put_power(acomp->dev, cookie);
- bus->display_power_active = 0;
- }
- }
}
EXPORT_SYMBOL_GPL(snd_hdac_display_power);
--
2.20.1
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