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",
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