From 9ad593f6d326e7a4664e3856520f6c042f82a37f Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 16 May 2008 12:34:47 +0200 Subject: [ALSA] hda - Fix DMA position inaccuracy Many HD-audio controllers seem inaccurate about the IRQ timing of PCM period updates. This has caused problems on audio quality; e.g. JACK doesn't work with two periods. This patch fixes the problem by checking the current DMA position at IRQ handler and delays the period-update via a workq if it's inaccurate. Signed-off-by: Takashi Iwai Signed-off-by: Jaroslav Kysela --- sound/pci/hda/hda_intel.c | 124 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 106 insertions(+), 18 deletions(-) diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index b3a618eb42cd..6ba7ac01d9f6 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -285,6 +285,7 @@ struct azx_dev { u32 *posbuf; /* position buffer pointer */ unsigned int bufsize; /* size of the play buffer in bytes */ + unsigned int period_bytes; /* size of the period in bytes */ unsigned int frags; /* number for period in the play buffer */ unsigned int fifo_size; /* FIFO size */ @@ -301,11 +302,10 @@ struct azx_dev { */ unsigned char stream_tag; /* assigned stream */ unsigned char index; /* stream index */ - /* for sanity check of position buffer */ - unsigned int period_intr; unsigned int opened :1; unsigned int running :1; + unsigned int irq_pending: 1; }; /* CORB/RIRB */ @@ -369,6 +369,9 @@ struct azx { /* for debugging */ unsigned int last_cmd; /* last issued command (to sync) */ + + /* for pending irqs */ + struct work_struct irq_pending_work; }; /* driver types */ @@ -908,6 +911,8 @@ static void azx_init_pci(struct azx *chip) } +static int azx_position_ok(struct azx *chip, struct azx_dev *azx_dev); + /* * interrupt handler */ @@ -930,11 +935,18 @@ static irqreturn_t azx_interrupt(int irq, void *dev_id) azx_dev = &chip->azx_dev[i]; if (status & azx_dev->sd_int_sta_mask) { azx_sd_writeb(azx_dev, SD_STS, SD_INT_MASK); - if (azx_dev->substream && azx_dev->running) { - azx_dev->period_intr++; + if (!azx_dev->substream || !azx_dev->running) + continue; + /* check whether this IRQ is really acceptable */ + if (azx_position_ok(chip, azx_dev)) { + azx_dev->irq_pending = 0; spin_unlock(&chip->reg_lock); snd_pcm_period_elapsed(azx_dev->substream); spin_lock(&chip->reg_lock); + } else { + /* bogus IRQ, process it later */ + azx_dev->irq_pending = 1; + schedule_work(&chip->irq_pending_work); } } } @@ -973,6 +985,7 @@ static int azx_setup_periods(struct snd_pcm_substream *substream, azx_sd_writel(azx_dev, SD_BDLPU, 0); period_bytes = snd_pcm_lib_period_bytes(substream); + azx_dev->period_bytes = period_bytes; periods = azx_dev->bufsize / period_bytes; /* program the initial BDL entries */ @@ -1421,27 +1434,16 @@ static int azx_pcm_trigger(struct snd_pcm_substream *substream, int cmd) return 0; } -static snd_pcm_uframes_t azx_pcm_pointer(struct snd_pcm_substream *substream) +static unsigned int azx_get_position(struct azx *chip, + struct azx_dev *azx_dev) { - struct azx_pcm *apcm = snd_pcm_substream_chip(substream); - struct azx *chip = apcm->chip; - struct azx_dev *azx_dev = get_azx_dev(substream); unsigned int pos; if (chip->position_fix == POS_FIX_POSBUF || chip->position_fix == POS_FIX_AUTO) { /* use the position buffer */ pos = le32_to_cpu(*azx_dev->posbuf); - if (chip->position_fix == POS_FIX_AUTO && - azx_dev->period_intr == 1 && !pos) { - printk(KERN_WARNING - "hda-intel: Invalid position buffer, " - "using LPIB read method instead.\n"); - chip->position_fix = POS_FIX_NONE; - goto read_lpib; - } } else { - read_lpib: /* read LPIB */ pos = azx_sd_readl(azx_dev, SD_LPIB); if (chip->position_fix == POS_FIX_FIFO) @@ -1449,7 +1451,90 @@ static snd_pcm_uframes_t azx_pcm_pointer(struct snd_pcm_substream *substream) } if (pos >= azx_dev->bufsize) pos = 0; - return bytes_to_frames(substream->runtime, pos); + return pos; +} + +static snd_pcm_uframes_t azx_pcm_pointer(struct snd_pcm_substream *substream) +{ + struct azx_pcm *apcm = snd_pcm_substream_chip(substream); + struct azx *chip = apcm->chip; + struct azx_dev *azx_dev = get_azx_dev(substream); + return bytes_to_frames(substream->runtime, + azx_get_position(chip, azx_dev)); +} + +/* + * Check whether the current DMA position is acceptable for updating + * periods. Returns non-zero if it's OK. + * + * Many HD-audio controllers appear pretty inaccurate about + * the update-IRQ timing. The IRQ is issued before actually the + * data is processed. So, we need to process it afterwords in a + * workqueue. + */ +static int azx_position_ok(struct azx *chip, struct azx_dev *azx_dev) +{ + unsigned int pos; + + pos = azx_get_position(chip, azx_dev); + if (chip->position_fix == POS_FIX_AUTO) { + if (!pos) { + printk(KERN_WARNING + "hda-intel: Invalid position buffer, " + "using LPIB read method instead.\n"); + chip->position_fix = POS_FIX_NONE; + pos = azx_get_position(chip, azx_dev); + } else + chip->position_fix = POS_FIX_POSBUF; + } + + if (pos % azx_dev->period_bytes > azx_dev->period_bytes / 2) + return 0; /* NG - it's below the period boundary */ + return 1; /* OK, it's fine */ +} + +/* + * The work for pending PCM period updates. + */ +static void azx_irq_pending_work(struct work_struct *work) +{ + struct azx *chip = container_of(work, struct azx, irq_pending_work); + int i, pending; + + for (;;) { + pending = 0; + spin_lock_irq(&chip->reg_lock); + for (i = 0; i < chip->num_streams; i++) { + struct azx_dev *azx_dev = &chip->azx_dev[i]; + if (!azx_dev->irq_pending || + !azx_dev->substream || + !azx_dev->running) + continue; + if (azx_position_ok(chip, azx_dev)) { + azx_dev->irq_pending = 0; + spin_unlock(&chip->reg_lock); + snd_pcm_period_elapsed(azx_dev->substream); + spin_lock(&chip->reg_lock); + } else + pending++; + } + spin_unlock_irq(&chip->reg_lock); + if (!pending) + return; + cond_resched(); + } +} + +/* clear irq_pending flags and assure no on-going workq */ +static void azx_clear_irq_pending(struct azx *chip) +{ + int i; + + spin_lock_irq(&chip->reg_lock); + for (i = 0; i < chip->num_streams; i++) + chip->azx_dev[i].irq_pending = 0; + spin_unlock_irq(&chip->reg_lock); + flush_scheduled_work(); } static struct snd_pcm_ops azx_pcm_ops = { @@ -1676,6 +1761,7 @@ static int azx_suspend(struct pci_dev *pci, pm_message_t state) int i; snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); + azx_clear_irq_pending(chip); for (i = 0; i < AZX_MAX_PCMS; i++) snd_pcm_suspend_all(chip->pcm[i]); if (chip->initialized) @@ -1732,6 +1818,7 @@ static int azx_free(struct azx *chip) int i; if (chip->initialized) { + azx_clear_irq_pending(chip); for (i = 0; i < chip->num_streams; i++) azx_stream_stop(chip, &chip->azx_dev[i]); azx_stop_chip(chip); @@ -1857,6 +1944,7 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci, chip->irq = -1; chip->driver_type = driver_type; chip->msi = enable_msi; + INIT_WORK(&chip->irq_pending_work, azx_irq_pending_work); chip->position_fix = check_position_fix(chip, position_fix[dev]); check_probe_mask(chip, dev); -- cgit v1.2.2