On Sat, 07 Dec 2019 21:06:43 +0100, Klaus Ethgen wrote:
Hi Takashi,
Am Mi den 4. Dez 2019 um 17:31 schrieb Takashi Iwai:
I guess checking the perf output would give you more clue, e.g. which function is hogging the CPU. Without such information, it's very hard to diagnose...
No problem, I just had the problem today again.
Find attached the perf output of the relevant event handler.
Thanks. So it seems wasting in the busy loop for waiting for the response from the codec.
How about a patch below? It's untested, might break things, but at least avoiding a busy loop.
BTW, if your machine is Coffeelake or Cannonlake, this patch wont' work on the old branch because of forced polling mode. It was removed in 5.5-rc1, so please test with Linus tree at best.
Takashi
--- a/include/sound/hdaudio.h +++ b/include/sound/hdaudio.h @@ -317,6 +317,7 @@ struct hdac_bus { struct hdac_rb corb; struct hdac_rb rirb; unsigned int last_cmd[HDA_MAX_CODECS]; /* last sent command */ + wait_queue_head_t rirb_waitq;
/* CORB/RIRB and position buffers */ struct snd_dma_buffer rb; diff --git a/sound/hda/hdac_bus.c b/sound/hda/hdac_bus.c index 8f19876244eb..5eb58fce5353 100644 --- a/sound/hda/hdac_bus.c +++ b/sound/hda/hdac_bus.c @@ -43,6 +43,7 @@ int snd_hdac_bus_init(struct hdac_bus *bus, struct device *dev, mutex_init(&bus->cmd_mutex); mutex_init(&bus->lock); INIT_LIST_HEAD(&bus->hlink_list); + init_waitqueue_head(&bus->rirb_waitq); bus->irq = -1; return 0; } diff --git a/sound/hda/hdac_controller.c b/sound/hda/hdac_controller.c index 7e7be8e4dcf9..cd8fa9aa599d 100644 --- a/sound/hda/hdac_controller.c +++ b/sound/hda/hdac_controller.c @@ -216,6 +216,9 @@ void snd_hdac_bus_update_rirb(struct hdac_bus *bus) else if (bus->rirb.cmds[addr]) { bus->rirb.res[addr] = res; bus->rirb.cmds[addr]--; + if (!bus->rirb.cmds[addr] && + waitqueue_active(&bus->rirb_waitq)) + wake_up(&bus->rirb_waitq); } else { dev_err_ratelimited(bus->dev, "spurious response %#x:%#x, last cmd=%#08x\n", diff --git a/sound/pci/hda/hda_controller.c b/sound/pci/hda/hda_controller.c index 2f3b7a35f2d9..56cafd12fa8a 100644 --- a/sound/pci/hda/hda_controller.c +++ b/sound/pci/hda/hda_controller.c @@ -792,21 +792,25 @@ static int azx_rirb_get_response(struct hdac_bus *bus, unsigned int addr, struct hda_bus *hbus = &chip->bus; unsigned long timeout; unsigned long loopcounter; - int do_poll = 0; + wait_queue_entry_t wait; bool warned = false;
+ init_wait_entry(&wait, 0); again: timeout = jiffies + msecs_to_jiffies(1000);
for (loopcounter = 0;; loopcounter++) { spin_lock_irq(&bus->reg_lock); - if (bus->polling_mode || do_poll) + if (!bus->polling_mode) + prepare_to_wait(&bus->rirb_waitq, &wait, + TASK_UNINTERRUPTIBLE); + if (bus->polling_mode) snd_hdac_bus_update_rirb(bus); if (!bus->rirb.cmds[addr]) { - if (!do_poll) - bus->poll_count = 0; if (res) *res = bus->rirb.res[addr]; /* the last value */ + if (!bus->polling_mode) + finish_wait(&bus->rirb_waitq, &wait); spin_unlock_irq(&bus->reg_lock); return 0; } @@ -814,7 +818,9 @@ static int azx_rirb_get_response(struct hdac_bus *bus, unsigned int addr, if (time_after(jiffies, timeout)) break; #define LOOP_COUNT_MAX 3000 - if (hbus->needs_damn_long_delay || + if (!bus->polling_mode) { + schedule_timeout(msecs_to_jiffies(2)); + } else if (hbus->needs_damn_long_delay || loopcounter > LOOP_COUNT_MAX) { if (loopcounter > LOOP_COUNT_MAX && !warned) { dev_dbg_ratelimited(chip->card->dev, @@ -829,19 +835,12 @@ static int azx_rirb_get_response(struct hdac_bus *bus, unsigned int addr, } }
+ if (!bus->polling_mode) + finish_wait(&bus->rirb_waitq, &wait); + if (hbus->no_response_fallback) return -EIO;
- if (!bus->polling_mode && bus->poll_count < 2) { - dev_dbg(chip->card->dev, - "azx_get_response timeout, polling the codec once: last cmd=0x%08x\n", - bus->last_cmd[addr]); - do_poll = 1; - bus->poll_count++; - goto again; - } - - if (!bus->polling_mode) { dev_warn(chip->card->dev, "azx_get_response timeout, switching to polling mode: last cmd=0x%08x\n",