On Fri, May 19, 2017 at 08:27:40AM +0200, Takashi Iwai wrote: > On Fri, 19 May 2017 05:57:05 +0200, > Takashi Sakamoto wrote: > > > > Hi, > > > > On May 16 2017 10:01, Subhransu S. Prusty wrote: > > > From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> > > > > > > When appl_ptr is updated let low-level driver know, e.g. to let the > > > low-level driver/hardware pre-fetch data opportunistically. > > > > > > The existing .ack callback is extended with new attribute argument, to > > > support this capability. Legacy driver subscribe to SND_PCM_ACK_LEGACY and > > > doesn't process ack if it is not set. SND_PCM_ACK_APP_PTR can be used to > > > process the application ptr update in the driver like in the skylake > > > driver which can use this to inform position of appl pointer to host DMA > > > controller. The skylake driver to process the SND_PCM_ACK_APP_PTR will be > > > submitted with a separate patch set. > > > > > > In the ALSA core, this capability is independent from the NO_REWIND > > > hardware flag. The low-level driver may however tie both options and only > > > use the updated appl_ptr when rewinds are disabled due to hardware > > > limitations. > > > > > > Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> > > > Signed-off-by: Jaikrishna Nemallapudi <jaikrishnax.nemallapudi@xxxxxxxxx> > > > Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@xxxxxxxxx> > > > --- > > > include/sound/pcm-indirect.h | 4 ++-- > > > include/sound/pcm.h | 8 +++++++- > > > sound/core/pcm_lib.c | 6 ++++-- > > > sound/core/pcm_native.c | 24 +++++++++++++++++++++++- > > > sound/mips/hal2.c | 14 +++++++++++--- > > > sound/pci/cs46xx/cs46xx_lib.c | 18 ++++++++++++++---- > > > sound/pci/emu10k1/emupcm.c | 8 ++++++-- > > > sound/pci/rme32.c | 15 ++++++++++++--- > > > 8 files changed, 79 insertions(+), 18 deletions(-) > > > > I think it better to take care of > > 'drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c' as > > well. This is a driver for sound functionality of Raspberry PI 1/zero > > and some people may still get influences from this work. > > > > $ git grep -A20 'struct snd_pcm_ops' v4.12-rc1 | grep \\.ack > > v4.12-rc1:drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c-... > > ... > > Yep, we need to cover all codes if we really change the PCM ops. Yes and fortunately there are a large set, so conversion is not a big issue here, converging to best approach is :) -- ~Vinod _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
