lkml.org 
[lkml]   [2011]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [BUG][2.6.38] IRQ Lock Inversion / i915 fails
Thanks a lot. That patch below does indeed
solve the irq lock inversion problem.

cu,
Knut

>
> The trigger callback should be called always in irq-disabled context,
> so this should be OK. But loopback_pos_update() is called in the
> timer callback, and this can be the issue.
>
> Knut, how about the patch below?
>
>
> thanks,
>
> Takashi
>
> ---
> diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
> index 12b44b0..a0da775 100644
> --- a/sound/drivers/aloop.c
> +++ b/sound/drivers/aloop.c
> @@ -482,8 +482,9 @@ static unsigned int loopback_pos_update(struct loopback_cable *cable)
> cable->streams[SNDRV_PCM_STREAM_CAPTURE];
> unsigned long delta_play = 0, delta_capt = 0;
> unsigned int running;
> + unsigned long flags;
>
> - spin_lock(&cable->lock);
> + spin_lock_irqsave(&cable->lock, flags);
> running = cable->running ^ cable->pause;
> if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
> delta_play = jiffies - dpcm_play->last_jiffies;
> @@ -495,10 +496,8 @@ static unsigned int loopback_pos_update(struct loopback_cable *cable)
> dpcm_capt->last_jiffies += delta_capt;
> }
>
> - if (delta_play == 0 && delta_capt == 0) {
> - spin_unlock(&cable->lock);
> - return running;
> - }
> + if (delta_play == 0 && delta_capt == 0)
> + goto unlock;
>
> if (delta_play > delta_capt) {
> loopback_bytepos_update(dpcm_play, delta_play - delta_capt,
> @@ -510,14 +509,14 @@ static unsigned int loopback_pos_update(struct loopback_cable *cable)
> delta_capt = delta_play;
> }
>
> - if (delta_play == 0 && delta_capt == 0) {
> - spin_unlock(&cable->lock);
> - return running;
> - }
> + if (delta_play == 0 && delta_capt == 0)
> + goto unlock;
> +
> /* note delta_capt == delta_play at this moment */
> loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY);
> loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY);
> - spin_unlock(&cable->lock);
> + unlock:
> + spin_unlock_irqrestore(&cable->lock, flags);
> return running;
> }
>
>



\
 
 \ /
  Last update: 2011-03-18 00:15    [from the cache]
©2003-2011 Jasper Spaans