Hi,
On Wed, Dec 26, 2018 at 11:28:11AM +0000, S.j. Wang wrote:
In the case that alsa driver can't support period wakeup, we need to set the no period wakeup flag
Signed-off-by: Shengjiu Wang shengjiu.wang@nxp.com
aplay/aplay.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/aplay/aplay.c b/aplay/aplay.c index efc1eb4cae3a..4f562bfe2884 100644 --- a/aplay/aplay.c +++ b/aplay/aplay.c @@ -137,6 +137,7 @@ static int use_strftime = 0; volatile static int recycle_capture_file = 0; static long term_c_lflag = -1; static int dump_hw_params = 0; +static int no_period_wakeup = 0;
static int fd = -1; static off64_t pbrec_count = LLONG_MAX, fdcount; @@ -243,6 +244,7 @@ _("Usage: %s [OPTION]... [FILE]...\n" " --use-strftime apply the strftime facility to the output file name\n" " --dump-hw-params dump hw_params of the device\n" " --fatal-errors treat all errors as fatal\n" +" --no-period-wakeup set no period wakeup flag if necessary\n" ) , command); printf(_("Recognized sample formats are:")); @@ -429,6 +431,7 @@ enum { OPT_USE_STRFTIME, OPT_DUMP_HWPARAMS, OPT_FATAL_ERRORS,
- OPT_NO_PERIOD_WAKEUP,
};
/* @@ -516,6 +519,7 @@ int main(int argc, char *argv[]) {"interactive", 0, 0, 'i'}, {"dump-hw-params", 0, 0, OPT_DUMP_HWPARAMS}, {"fatal-errors", 0, 0, OPT_FATAL_ERRORS},
{"no-period-wakeup", 0, 0, OPT_NO_PERIOD_WAKEUP},#ifdef CONFIG_SUPPORT_CHMAP {"chmap", 1, 0, 'm'}, #endif @@ -799,6 +803,9 @@ int main(int argc, char *argv[]) case OPT_FATAL_ERRORS: fatal_errors = 1; break;
case OPT_NO_PERIOD_WAKEUP:no_period_wakeup = 1;break;#ifdef CONFIG_SUPPORT_CHMAP case 'm': channel_map = snd_pcm_chmap_parse_string(optarg); @@ -1396,6 +1403,12 @@ static void set_params(void) &buffer_frames); } assert(err >= 0);
- if (no_period_wakeup) {
err = snd_pcm_hw_params_set_period_wakeup(handle, params, 0);assert(err >= 0);- }
- monotonic = snd_pcm_hw_params_is_monotonic(params); can_pause = snd_pcm_hw_params_can_pause(params); err = snd_pcm_hw_params(handle, params);
-- 1.9.1
As of v4.21-rc1, runtime of PCM substream can't run no_period_wakeup mode unless two conditions are satisfied[1]: - driver supports SNDRV_PCM_INFO_NO_PERIOD_WAKEUP - PCM applications set SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP flag to hardware parameter structure.
Neither alsa-lib nor the most of existent userspace applications set SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP without explicit call of helper API. In this point, I can get your intention for this patch. If a driver just supports no_period_wakeup mode, such driver can't work well.
However, such driver is problematic because apparently it can not run with many existent userspace applications and alsa-lib. Before applying this patch, we have enough discussion to prevent problems to introduce such problematic drivers into Linux sound subsystem, in my opinion.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/tree/sound/c...
Regards
Takashi Sakamoto