On 29/08/07 23:29 -0400, Andres Salomon wrote:
>
> In the suspend path, we currently save the PRD registers and then disable DMA.
> This is racy; the sound hardware might update the PRD register as it finishes
> processing some DMA pages between when we've saved the PRD registers and
> when DMA actually gets disabled. Furthermore, we actively check whether or
> not DMA is enabled before saving PRD registers; there's no reason to do that,
> as the PRD registers should not update when we twiddle the ACC_BM[x]_CMD
> register(s). Worst case, we save the PRD registers twice; even powering
> down the ACC shouldn't mess with the PRD registers (according to the 5536
> data sheet, section 5.3.7.4, power-down procedure). This patch reworks
> all that to first disable DMA, and then save PRD registers.
>
> Signed-off-by: Andres Salomon <[email protected]>
Acked-by: Jordan Crouse <[email protected]>
> ---
>
> sound/pci/cs5535audio/cs5535audio.h | 1 -
> sound/pci/cs5535audio/cs5535audio_pcm.c | 2 --
> sound/pci/cs5535audio/cs5535audio_pm.c | 14 +++++++-------
> 3 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/sound/pci/cs5535audio/cs5535audio.h b/sound/pci/cs5535audio/cs5535audio.h
> index 4fd1f31..c7a2044 100644
> --- a/sound/pci/cs5535audio/cs5535audio.h
> +++ b/sound/pci/cs5535audio/cs5535audio.h
> @@ -106,7 +106,6 @@ struct cs5535audio_dma {
> struct snd_pcm_substream *substream;
> unsigned int buf_addr, buf_bytes;
> unsigned int period_bytes, periods;
> - int suspended;
> u32 saved_prd;
> };
>
> diff --git a/sound/pci/cs5535audio/cs5535audio_pcm.c b/sound/pci/cs5535audio/cs5535audio_pcm.c
> index e61f972..fe21a1c 100644
> --- a/sound/pci/cs5535audio/cs5535audio_pcm.c
> +++ b/sound/pci/cs5535audio/cs5535audio_pcm.c
> @@ -300,14 +300,12 @@ static int snd_cs5535audio_trigger(struct snd_pcm_substream *substream, int cmd)
> break;
> case SNDRV_PCM_TRIGGER_RESUME:
> dma->ops->enable_dma(cs5535au);
> - dma->suspended = 0;
> break;
> case SNDRV_PCM_TRIGGER_STOP:
> dma->ops->disable_dma(cs5535au);
> break;
> case SNDRV_PCM_TRIGGER_SUSPEND:
> dma->ops->disable_dma(cs5535au);
> - dma->suspended = 1;
> break;
> default:
> snd_printk(KERN_ERR "unhandled trigger\n");
> diff --git a/sound/pci/cs5535audio/cs5535audio_pm.c b/sound/pci/cs5535audio/cs5535audio_pm.c
> index 3e4d198..9a4e84a 100644
> --- a/sound/pci/cs5535audio/cs5535audio_pm.c
> +++ b/sound/pci/cs5535audio/cs5535audio_pm.c
> @@ -64,13 +64,13 @@ int snd_cs5535audio_suspend(struct pci_dev *pci, pm_message_t state)
> int i;
>
> snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
> + snd_pcm_suspend_all(cs5535au->pcm);
> + snd_ac97_suspend(cs5535au->ac97);
> for (i = 0; i < NUM_CS5535AUDIO_DMAS; i++) {
> struct cs5535audio_dma *dma = &cs5535au->dmas[i];
> - if (dma && dma->substream && !dma->suspended)
> + if (dma && dma->substream)
> dma->saved_prd = dma->ops->read_prd(cs5535au);
> }
> - snd_pcm_suspend_all(cs5535au->pcm);
> - snd_ac97_suspend(cs5535au->ac97);
> /* save important regs, then disable aclink in hw */
> snd_cs5535audio_stop_hardware(cs5535au);
>
> @@ -112,17 +112,17 @@ int snd_cs5535audio_resume(struct pci_dev *pci)
> if (!timeout)
> snd_printk(KERN_ERR "Failure getting AC Link ready\n");
>
> - /* we depend on ac97 to perform the codec power up */
> - snd_ac97_resume(cs5535au->ac97);
> /* set up rate regs, dma. actual initiation is done in trig */
> for (i = 0; i < NUM_CS5535AUDIO_DMAS; i++) {
> struct cs5535audio_dma *dma = &cs5535au->dmas[i];
> - if (dma && dma->substream && dma->suspended) {
> + if (dma && dma->substream) {
> dma->substream->ops->prepare(dma->substream);
> dma->ops->setup_prd(cs5535au, dma->saved_prd);
> }
> }
> -
> +
> + /* we depend on ac97 to perform the codec power up */
> + snd_ac97_resume(cs5535au->ac97);
> snd_power_change_state(card, SNDRV_CTL_POWER_D0);
>
> return 0;
>
>
--
Jordan Crouse
Systems Software Development Engineer
Advanced Micro Devices, Inc.
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