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authorTakashi Iwai <tiwai@suse.de>2009-06-15 12:31:38 +0200
committerTakashi Iwai <tiwai@suse.de>2009-06-15 12:36:06 +0200
commitf708eb1d71dc8ffb184da9f0bc53461c6dc10653 (patch)
tree195e50b4208033255cdcd5471b4dec3cb796497a /sound
parent07a2039b8eb0af4ff464efd3dfd95de5c02648c6 (diff)
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ALSA: intel8x0 - Fix PCM position craziness
The PCM pointer callback sometimes returns invalid positions and this screws up the hw_ptr updater in PCM core. Especially since now the jiffies check is optional with xrun_debug, the invalid position is handled as is, and causes serious sound skips, etc. This patch simplifies the position-fix strategy in intel8x0 to be more robust: - just falls back to the last position if bogus position is detected - another sanity check for the backward move of the position due to a race of register update and the base-index update This patch is applicable also for 2.6.30. Tested-by: David Miller <davem@davemloft.net> Cc: <stable@kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
-rw-r--r--sound/pci/intel8x0.c24
1 files changed, 12 insertions, 12 deletions
diff --git a/sound/pci/intel8x0.c b/sound/pci/intel8x0.c
index 173bebf9f51..8aa5687f392 100644
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -356,8 +356,6 @@ struct ichdev {
unsigned int position;
unsigned int pos_shift;
unsigned int last_pos;
- unsigned long last_pos_jiffies;
- unsigned int jiffy_to_bytes;
int frags;
int lvi;
int lvi_frag;
@@ -844,7 +842,6 @@ static int snd_intel8x0_pcm_trigger(struct snd_pcm_substream *substream, int cmd
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
val = ICH_IOCE | ICH_STARTBM;
ichdev->last_pos = ichdev->position;
- ichdev->last_pos_jiffies = jiffies;
break;
case SNDRV_PCM_TRIGGER_SUSPEND:
ichdev->suspended = 1;
@@ -1048,7 +1045,6 @@ static int snd_intel8x0_pcm_prepare(struct snd_pcm_substream *substream)
ichdev->pos_shift = (runtime->sample_bits > 16) ? 2 : 1;
}
snd_intel8x0_setup_periods(chip, ichdev);
- ichdev->jiffy_to_bytes = (runtime->rate * 4 * ichdev->pos_shift) / HZ;
return 0;
}
@@ -1073,19 +1069,23 @@ static snd_pcm_uframes_t snd_intel8x0_pcm_pointer(struct snd_pcm_substream *subs
ptr1 == igetword(chip, ichdev->reg_offset + ichdev->roff_picb))
break;
} while (timeout--);
+ ptr = ichdev->last_pos;
if (ptr1 != 0) {
ptr1 <<= ichdev->pos_shift;
ptr = ichdev->fragsize1 - ptr1;
ptr += position;
- ichdev->last_pos = ptr;
- ichdev->last_pos_jiffies = jiffies;
- } else {
- ptr1 = jiffies - ichdev->last_pos_jiffies;
- if (ptr1)
- ptr1 -= 1;
- ptr = ichdev->last_pos + ptr1 * ichdev->jiffy_to_bytes;
- ptr %= ichdev->size;
+ if (ptr < ichdev->last_pos) {
+ unsigned int pos_base, last_base;
+ pos_base = position / ichdev->fragsize1;
+ last_base = ichdev->last_pos / ichdev->fragsize1;
+ /* another sanity check; ptr1 can go back to full
+ * before the base position is updated
+ */
+ if (pos_base == last_base)
+ ptr = ichdev->last_pos;
+ }
}
+ ichdev->last_pos = ptr;
spin_unlock(&chip->reg_lock);
if (ptr >= ichdev->size)
return 0;