Re: [alsa-devel] Is locking problem in snd_intel8x0_pcm_pointer() ?

At Mon, 24 Oct 2011 15:48:44 +0400, Konstantin Ozerkov wrote:

Seems that locking is broken: snd_intel8x0_pcm_pointer() uses spin_lock()/spin_unlock() semantic for lock which is shared in ISR ( snd_intel8x0_update). As result we got possible deadlock inside ISR on UP system. And needed special kludge inside snd_intel8x0_pcm_pointer() to prevent moving backward (really this is race with snd_intel8x0_update).

Hm, could you elaborate how can it a problem? snd_intel8x0_update() releases the lock before calling snd_pcm_period_update() that calls the pointer callback.

Takashi