snd_hdac_display_power() doesn't handle the concurrent calls carefully enough, and it may lead to the doubly get_power or put_power calls, when a runtime PM and an async work get called in racy way.

This patch addresses it by reusing the bus->lock mutex that has been used for protecting the link state change in ext bus code, so that it can protect against racy display state changes. The initialization of bus->lock was moved from snd_hdac_ext_bus_init() to snd_hdac_bus_init() as well accordingly.

Testcase: igt/i915_pm_rpm/module-reload #glk-dsi Reported-by: Chris Wilson chris@chris-wilson.co.uk Reviewed-by: Chris Wilson chris@chris-wilson.co.uk Cc: Imre Deak imre.deak@intel.com Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/hda/ext/hdac_ext_bus.c | 1 - sound/hda/hdac_bus.c | 1 + sound/hda/hdac_component.c | 6 +++++- 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/sound/hda/ext/hdac_ext_bus.c b/sound/hda/ext/hdac_ext_bus.c index 9c37d9af3023..ec7715c6b0c0 100644 --- a/sound/hda/ext/hdac_ext_bus.c +++ b/sound/hda/ext/hdac_ext_bus.c @@ -107,7 +107,6 @@ int snd_hdac_ext_bus_init(struct hdac_bus *bus, struct device *dev, INIT_LIST_HEAD(&bus->hlink_list); bus->idx = idx++;

- mutex_init(&bus->lock); bus->cmd_dma_state = true;

return 0; diff --git a/sound/hda/hdac_bus.c b/sound/hda/hdac_bus.c index 012305177f68..ad8eee08013f 100644 --- a/sound/hda/hdac_bus.c +++ b/sound/hda/hdac_bus.c @@ -38,6 +38,7 @@ int snd_hdac_bus_init(struct hdac_bus *bus, struct device *dev, INIT_WORK(&bus->unsol_work, snd_hdac_bus_process_unsol_events); spin_lock_init(&bus->reg_lock); mutex_init(&bus->cmd_mutex); + mutex_init(&bus->lock); bus->irq = -1; return 0; } diff --git a/sound/hda/hdac_component.c b/sound/hda/hdac_component.c index a6d37b9d6413..6b5caee61c6e 100644 --- a/sound/hda/hdac_component.c +++ b/sound/hda/hdac_component.c @@ -69,13 +69,15 @@ void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx, bool enable)

dev_dbg(bus->dev, "display power %s\n", enable ? "enable" : "disable"); + + mutex_lock(&bus->lock); if (enable) set_bit(idx, &bus->display_power_status); else clear_bit(idx, &bus->display_power_status);

if (!acomp || !acomp->ops) - return; + goto unlock;

if (bus->display_power_status) { if (!bus->display_power_active) { @@ -92,6 +94,8 @@ void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx, bool enable) bus->display_power_active = false; } } + unlock: + mutex_unlock(&bus->lock); } EXPORT_SYMBOL_GPL(snd_hdac_display_power);