>-----Original Message----- >From: Takashi Iwai [mailto:tiwai@xxxxxxx] >Sent: Sunday, June 14, 2009 4:16 PM >To: Mark Brown >Cc: Mike Frysinger; Karl Beldan; >uclinux-dist-devel@xxxxxxxxxxxxxxxxxxxx; >alsa-devel@xxxxxxxxxxxxxxxx; Cai, Cliff >Subject: Re: [Uclinux-dist-devel] [PATCH 2/5] >ASoC codec: SSM2602: assign last substream to the master when >shutting down > >At Sat, 13 Jun 2009 12:06:07 +0100, >Mark Brown wrote: >> >> On Sat, Jun 13, 2009 at 07:03:12AM -0400, Mike Frysinger wrote: >> >> > the first part conditionalized the constraints. ignoring >whitespace >> > changes, this is the diff: >> > +if (master_runtime->rate != 0) >> > snd_pcm_hw_constraint_minmax(substream->runtime, >> > ...... >> > +if (master_runtime->sample_bits != 0) >> > snd_pcm_hw_constraint_minmax(substream->runtime, >> > ...... >> >> > or maybe that is what you're saying and i dont know alsa >> >> That's not a bad change - there's a thin race condition if you >> simultaneously start up two applications where the primary substream >> could be there but not yet configured since stream startup >is separate >> to the configuration of the stream. It's hard but not impossible to >> reproduce. > >An absolute race-free hw-constraint for multiple substreams is >actually difficult to implement. The best practice would be >to give an error and refuse the change when any inconsistency >occurs, IMO. > Without this patch, Oss-based applications (such as "tone","vplay" etc.) won't work properly. Cliff _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
