Hi, On Wed, 3 Feb 2010, Raymond Yau wrote: >> - the 'only' change is to make sure the hw_ptr reported in .pointer is >> NOT the number of samples pushed out to the interface. hw_ptr should [...] > if snd_xxx_pointer call back return the next read position , the hw_ptr will > always be multiple of PCI/PCIe brust size yep, that's the point I was trying to make in my longish earlier mail yesterday: http://article.gmane.org/gmane.linux.alsa.devel/70306 I also presented two solutions for this. So let hw_ptr be a multiple of burst/batch size, but compensate by: 1) driver updates runtime->delay in its pointer() callback, or -> finegrained playout delay can be reported even if hw_ptr is a multiple of burst/batch size 2) use of snd_pcm_status_get_tstamp() (original idea from Eero) -> assumes runtime->delay is updated in sync with hw_ptr Both are possible with existing ALSA infra, and driver and app developers could just use these, but what is missing is the consensus whether this is a valid/allowed thing to do and rely on. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
