[PATCH] staging: vc4_services: bcm2835-audio: Add SNDRV_PCM_INFO_BATCH flag

[Dylan Van Assche]

Playing audio with PulseAudio and the bcm2835-pcm driver results
in distorted sound. Timer-based scheduling does not properly work
with bcm2835-pcm since configuring PulseAudio with tsched=0
avoids this problem.

Setting the SNDRV_PCM_INFO_BATCH flag prevents PulseAudio to use
timer-based scheduling by default. Settings this flag makes audio
works out of the box.

Based on: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7f2430cda819a9ecb1df5a0f3ef4f1c20db3f811

Signed-off-by: Dylan Van Assche <me at dylanvanassche.be>
---
Tested on my Raspberry Pi 3B+ with Kodi and postmarketOS.

 drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
index f783b632141b..1c200b923dfd 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
@@ -12,7 +12,7 @@
 static const struct snd_pcm_hardware snd_bcm2835_playback_hw = {
 	.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
 		 SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
-		 SNDRV_PCM_INFO_SYNC_APPLPTR),
+		 SNDRV_PCM_INFO_SYNC_APPLPTR | SNDRV_PCM_INFO_BATCH),
 	.formats = SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE,
 	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
 	.rate_min = 8000,
@@ -29,7 +29,7 @@ static const struct snd_pcm_hardware snd_bcm2835_playback_hw = {
 static const struct snd_pcm_hardware snd_bcm2835_playback_spdif_hw = {
 	.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
 		 SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
-		 SNDRV_PCM_INFO_SYNC_APPLPTR),
+		 SNDRV_PCM_INFO_SYNC_APPLPTR | SNDRV_PCM_INFO_BATCH),
 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
 	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_44100 |
 	SNDRV_PCM_RATE_48000,
-- 
2.30.0