> -----Original Message----- > From: Sia, Jee Heng <jee.heng.sia@xxxxxxxxx> > Sent: Tuesday, 8 December, 2020 11:21 AM > To: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>; > Lars-Peter Clausen <lars@xxxxxxxxxx>; Sit, Michael Wei Hong > <michael.wei.hong.sit@xxxxxxxxx>; Shevchenko, Andriy > <andriy.shevchenko@xxxxxxxxx> > Cc: Rojewski, Cezary <cezary.rojewski@xxxxxxxxx>; alsa- > devel@xxxxxxxxxxxxxxxx; tiwai@xxxxxxxx; > liam.r.girdwood@xxxxxxxxxxxxxxx; vkoul@xxxxxxxxxx; > broonie@xxxxxxxxxx > Subject: RE: [RFC PATCH 2/4] ASoC: soc-generic-dmaengine-pcm: > Add custom prepare and submit function > > > > > -----Original Message----- > > From: Pierre-Louis Bossart <pierre- > louis.bossart@xxxxxxxxxxxxxxx> > > Sent: 07 December 2020 11:36 PM > > To: Lars-Peter Clausen <lars@xxxxxxxxxx>; Sit, Michael Wei > Hong > > <michael.wei.hong.sit@xxxxxxxxx>; Sia, Jee Heng > > <jee.heng.sia@xxxxxxxxx>; Shevchenko, Andriy > > <andriy.shevchenko@xxxxxxxxx> > > Cc: Rojewski, Cezary <cezary.rojewski@xxxxxxxxx>; alsa- > devel@alsa- > > project.org; tiwai@xxxxxxxx; liam.r.girdwood@xxxxxxxxxxxxxxx; > > vkoul@xxxxxxxxxx; broonie@xxxxxxxxxx > > Subject: Re: [RFC PATCH 2/4] ASoC: soc-generic-dmaengine- > pcm: Add > > custom prepare and submit function > > > > > > > > > > > If you really want to limit your period size you need to install a > > > range constraint on the > SNDRV_PCM_HW_PARAM_PERIOD_SIZE > > parameter. > > > > > > But I'd highly recommend against it and just split the transfer > into > > > multiple segments in the DMA driver. Needlessly limiting the > period > > > size will increase the number of interrupts during audio > > > playback/recording and hurt the power efficiency of your > system. > > > > Yes that was also an objection from me, the fix should be in the > DMA > > level. The 1024 block limitation would mean restricting the > period > > size to be at most 5.3 or 10.6ms (16 and 32-bit cases). That's way > to small. > [>>] Seems like complexity increases if splitting the segments in > ASoC. This is not a framework issue nor architecture issue. > If introducing new API to DMAENGINE to constraint the number > of items is not recommended, then lets split the segments in > DMA driver. With the increased complexity of introducing new APIs can we move the segment splitting to the DMA driver? Anymore concerns with doing so?
