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authorDavid Henningsson <david.henningsson@canonical.com>2012-05-04 11:05:55 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-21 09:40:01 -0700
commitb147567a79744253aa13c8266bfc48ceb70eff6c (patch)
treec31c8a9478b06c17d425fca2db56b7d1776b8a40 /sound
parent1a26c7d95b8f7715b1111f75693ef77385af44fa (diff)
ALSA: HDA: Lessen CPU usage when waiting for chip to respond
commit 32cf4023e689ad5b3a81a749d8cc99d7f184cb99 upstream. When an IRQ for some reason gets lost, we wait up to a second using udelay, which is CPU intensive. This patch improves the situation by waiting about 30 ms in the CPU intensive mode, then stepping down to using msleep(2) instead. In essence, we trade some granularity in exchange for less CPU consumption when the waiting time is a bit longer. As a result, PulseAudio should no longer be killed by the kernel for taking up to much RT-prio CPU time. At least not for *this* reason. Signed-off-by: David Henningsson <david.henningsson@canonical.com> Tested-by: Arun Raghavan <arun.raghavan@collabora.co.uk> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound')
-rw-r--r--sound/pci/hda/hda_intel.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 981b6fd1ae7c..c5c97880f505 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -702,11 +702,13 @@ static unsigned int azx_rirb_get_response(struct hda_bus *bus,
{
struct azx *chip = bus->private_data;
unsigned long timeout;
+ unsigned long loopcounter;
int do_poll = 0;
again:
timeout = jiffies + msecs_to_jiffies(1000);
- for (;;) {
+
+ for (loopcounter = 0;; loopcounter++) {
if (chip->polling_mode || do_poll) {
spin_lock_irq(&chip->reg_lock);
azx_update_rirb(chip);
@@ -722,7 +724,7 @@ static unsigned int azx_rirb_get_response(struct hda_bus *bus,
}
if (time_after(jiffies, timeout))
break;
- if (bus->needs_damn_long_delay)
+ if (bus->needs_damn_long_delay || loopcounter > 3000)
msleep(2); /* temporary workaround */
else {
udelay(10);