[ALSA] intel8x0: do not use zero value from PICB register
authorJaroslav Kysela <perex@perex.cz>
Mon, 13 Apr 2009 19:31:25 +0000 (21:31 +0200)
committerJaroslav Kysela <perex@perex.cz>
Mon, 13 Apr 2009 19:31:25 +0000 (21:31 +0200)
It seems that the zero value from the PICB (position in current buffer)
register is not reliable. Use jiffies to correct returned value
from the ring buffer pointer callback.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
sound/pci/intel8x0.c

index c86ff499460b1d62b291002d5c2990c7fd6092cd..6962f94d1beaf9de8790387ac1c5367cba273ac3 100644 (file)
@@ -355,6 +355,9 @@ struct ichdev {
         unsigned int fragsize1;
         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;
@@ -838,7 +841,10 @@ static int snd_intel8x0_pcm_trigger(struct snd_pcm_substream *substream, int cmd
                ichdev->suspended = 0;
                /* fallthru */
        case SNDRV_PCM_TRIGGER_START:
+       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;
@@ -849,9 +855,6 @@ static int snd_intel8x0_pcm_trigger(struct snd_pcm_substream *substream, int cmd
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                val = ICH_IOCE;
                break;
-       case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-               val = ICH_IOCE | ICH_STARTBM;
-               break;
        default:
                return -EINVAL;
        }
@@ -1045,6 +1048,7 @@ 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;
 }
 
@@ -1053,7 +1057,7 @@ static snd_pcm_uframes_t snd_intel8x0_pcm_pointer(struct snd_pcm_substream *subs
        struct intel8x0 *chip = snd_pcm_substream_chip(substream);
        struct ichdev *ichdev = get_ichdev(substream);
        size_t ptr1, ptr;
-       int civ, timeout = 100;
+       int civ, timeout = 10;
        unsigned int position;
 
        spin_lock(&chip->reg_lock);
@@ -1069,9 +1073,19 @@ 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--);
-       ptr1 <<= ichdev->pos_shift;
-       ptr = ichdev->fragsize1 - ptr1;
-       ptr += position;
+       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;
+       }
        spin_unlock(&chip->reg_lock);
        if (ptr >= ichdev->size)
                return 0;
@@ -2710,9 +2724,13 @@ static void __devinit intel8x0_measure_ac97_clock(struct intel8x0 *chip)
                    pos1 == igetword(chip, ichdev->reg_offset + ichdev->roff_picb))
                        break;
        } while (timeout--);
-       pos = ichdev->fragsize1;
-       pos -= pos1 << ichdev->pos_shift;
-       pos += ichdev->position;
+       if (pos1 == 0) {        /* oops, this value is not reliable */
+               pos = 0;
+       } else {
+               pos = ichdev->fragsize1;
+               pos -= pos1 << ichdev->pos_shift;
+               pos += ichdev->position;
+       }
        chip->in_measurement = 0;
        do_posix_clock_monotonic_gettime(&stop_time);
        /* stop */
@@ -2729,6 +2747,11 @@ static void __devinit intel8x0_measure_ac97_clock(struct intel8x0 *chip)
        iputbyte(chip, port + ICH_REG_OFF_CR, ICH_RESETREGS);
        spin_unlock_irq(&chip->reg_lock);
 
+       if (pos == 0) {
+               snd_printk(KERN_ERR "intel8x0: measure - unreliable DMA position..\n");
+               return;
+       }
+
        pos /= 4;
        t = stop_time.tv_sec - start_time.tv_sec;
        t *= 1000000;