-----Original Message----- From: Mark Brown [mailto:broonie@kernel.org] Sent: Monday, August 17, 2015 12:56 PM To: Fang, Yang A Cc: lgirdwood@gmail.com; alsa-devel@alsa-project.org; dgreid@chromium.org; Nujella, Sathyanarayana; kevin.strasser@linux.intel.com; Sripathi, Srinivas; Iriawan, Denny; Jain, Praveen K; Koul, Vinod; Mirche, Dinesh Subject: Re: [PATCH] ASoC: Intel: Bsw: Read sst DSP DMA pointer after period elapse occurs
On Sun, Aug 16, 2015 at 11:12:25PM -0700, yang.a.fang@intel.com wrote:
We should not read sst hw_ptr and pcm_delay in sst_platform_pcm_pointer Since it will be ricky if sst_platform_pcm_pointer is called while dsp is updating the timestamp.Now read sst hw_ptr after period elapse interrupt occurs.
So I guess there's still some risk that we could run into problems here if we take too long to service the interrupt and/or the period is very short? Is there anything we can do to improve that?
Hi Mark, I think before and after the patch. There is no difference in term of handling the period elapse interrupt . because before the patch sst_period_elapsed calls the snd_pcm_period_elapsed which in turn calling the sst_platform_pcm_pointer which calls the stream_read_tstamp.