On Thu, 10 Jun 2021 05:17:30 +0200, Takashi Sakamoto wrote: > > Hi, > > This patchset is revised version of my previous one: > * https://lore.kernel.org/alsa-devel/20210609143145.146680-1-o-takashi@xxxxxxxxxxxxx/ > > All of drivers in ALSA firewire stack have two chances to process > isochronous packets of any isochronous context; in software IRQ context > for 1394 OHCI, and in process context of ALSA PCM application. > > In the process context, callbacks of .pointer and .ack are utilized. The > callbacks are done by ALSA PCM core under acquiring lock of PCM substream, > > In design of ALSA PCM core, call of snd_pcm_period_elapsed() is used for > drivers to awaken user processes from waiting for available frames. The > function voluntarily acquires lock of PCM substream, therefore it is not > called in the process context since it causes dead lock. As a workaround > to avoid the dead lock, all of drivers in ALSA firewire stack use workqueue > to delegate the call. > > This patchset is my attempt for the issue. A variant of > 'snd_pcm_period_elapsed()' without lock acquisition is going to be added, > named 'snd_pcm_period_elapsed_under_stream_lock()'. The call is available > in callbacks of .pointer and .ack of snd_pcm_ops structure. > > Changes from v2: > * delete context section from kernel API documentation > > Takashi Sakamoto (3): > ALSA: pcm: add snd_pcm_period_elapsed() variant without acquiring lock > of PCM substream > ALSA: firewire-lib: operate for period elapse event in process context > ALSA: firewire-lib: obsolete workqueue for period update Applied all three patches now. Thanks. Takashi
