This patch implements the same logic that was done for the legacy HD-audio controller driver by the commit 88452da92ba2 ("ALSA: hda: Use standard waitqueue for RIRB wakeup") to the HDA-core helper code, too. This makes snd_hdac_bus_get_response() waiting for the response with bus->rirb_wq instead of polling when bus->polling is false. It'll save both CPU time and response latency.
Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/hda/hdac_controller.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/sound/hda/hdac_controller.c b/sound/hda/hdac_controller.c index cd1c3b282657..61950b83b8c9 100644 --- a/sound/hda/hdac_controller.c +++ b/sound/hda/hdac_controller.c @@ -241,30 +241,42 @@ int snd_hdac_bus_get_response(struct hdac_bus *bus, unsigned int addr, { unsigned long timeout; unsigned long loopcounter; + wait_queue_entry_t wait;
+ init_wait_entry(&wait, 0); timeout = jiffies + msecs_to_jiffies(1000);
for (loopcounter = 0;; loopcounter++) { spin_lock_irq(&bus->reg_lock); + if (!bus->polling_mode) + prepare_to_wait(&bus->rirb_wq, &wait, + TASK_UNINTERRUPTIBLE); if (bus->polling_mode) snd_hdac_bus_update_rirb(bus); if (!bus->rirb.cmds[addr]) { if (res) *res = bus->rirb.res[addr]; /* the last value */ + if (!bus->polling_mode) + finish_wait(&bus->rirb_wq, &wait); spin_unlock_irq(&bus->reg_lock); return 0; } spin_unlock_irq(&bus->reg_lock); if (time_after(jiffies, timeout)) break; - if (loopcounter > 3000) + if (!bus->polling_mode) { + schedule_timeout(msecs_to_jiffies(2)); + } else if (loopcounter > 3000) { msleep(2); /* temporary workaround */ - else { + } else { udelay(10); cond_resched(); } }
+ if (!bus->polling_mode) + finish_wait(&bus->rirb_wq, &wait); + return -EIO; } EXPORT_SYMBOL_GPL(snd_hdac_bus_get_response);