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authorMikhail Durnev <mikhail_durnev@mentor.com>2021-03-16 14:47:35 +1000
committerMark Brown <broonie@kernel.org>2021-03-16 13:29:37 +0000
commit19c6a63ced5e07e40f3a5255cb1f0fe0d3be7b14 (patch)
tree4aadbd7582b262f523cbde3903b8a127f183874a
parent1d49439c04792a4a3d8299a32b7673ab7ba13b77 (diff)
downloadlinux-19c6a63ced5e07e40f3a5255cb1f0fe0d3be7b14.tar.bz2
ASoC: rsnd: core: Check convert rate in rsnd_hw_params
snd_pcm_hw_params_set_rate_near can return incorrect sample rate in some cases, e.g. when the backend output rate is set to some value higher than 48000 Hz and the input rate is 8000 Hz. So passing the value returned by snd_pcm_hw_params_set_rate_near to snd_pcm_hw_params will result in "FSO/FSI ratio error" and playing no audio at all while the userland is not properly notified about the issue. If SRC is unable to convert the requested sample rate to the sample rate the backend is using, then the requested sample rate should be adjusted in rsnd_hw_params. The userland will be notified about that change in the returned hw_params structure. Signed-off-by: Mikhail Durnev <mikhail_durnev@mentor.com> Link: https://lore.kernel.org/r/1615870055-13954-1-git-send-email-mikhail_durnev@mentor.com Signed-off-by: Mark Brown <broonie@kernel.org>
-rw-r--r--sound/soc/sh/rcar/core.c69
1 files changed, 68 insertions, 1 deletions
diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
index d1612d35f0ee..8696a993c478 100644
--- a/sound/soc/sh/rcar/core.c
+++ b/sound/soc/sh/rcar/core.c
@@ -1424,8 +1424,75 @@ static int rsnd_hw_params(struct snd_soc_component *component,
}
if (io->converted_chan)
dev_dbg(dev, "convert channels = %d\n", io->converted_chan);
- if (io->converted_rate)
+ if (io->converted_rate) {
+ /*
+ * SRC supports convert rates from params_rate(hw_params)/k_down
+ * to params_rate(hw_params)*k_up, where k_up is always 6, and
+ * k_down depends on number of channels and SRC unit.
+ * So all SRC units can upsample audio up to 6 times regardless
+ * its number of channels. And all SRC units can downsample
+ * 2 channel audio up to 6 times too.
+ */
+ int k_up = 6;
+ int k_down = 6;
+ int channel;
+ struct rsnd_mod *src_mod = rsnd_io_to_mod_src(io);
+
dev_dbg(dev, "convert rate = %d\n", io->converted_rate);
+
+ channel = io->converted_chan ? io->converted_chan :
+ params_channels(hw_params);
+
+ switch (rsnd_mod_id(src_mod)) {
+ /*
+ * SRC0 can downsample 4, 6 and 8 channel audio up to 4 times.
+ * SRC1, SRC3 and SRC4 can downsample 4 channel audio
+ * up to 4 times.
+ * SRC1, SRC3 and SRC4 can downsample 6 and 8 channel audio
+ * no more than twice.
+ */
+ case 1:
+ case 3:
+ case 4:
+ if (channel > 4) {
+ k_down = 2;
+ break;
+ }
+ fallthrough;
+ case 0:
+ if (channel > 2)
+ k_down = 4;
+ break;
+
+ /* Other SRC units do not support more than 2 channels */
+ default:
+ if (channel > 2)
+ return -EINVAL;
+ }
+
+ if (params_rate(hw_params) > io->converted_rate * k_down) {
+ hw_param_interval(hw_params, SNDRV_PCM_HW_PARAM_RATE)->min =
+ io->converted_rate * k_down;
+ hw_param_interval(hw_params, SNDRV_PCM_HW_PARAM_RATE)->max =
+ io->converted_rate * k_down;
+ hw_params->cmask |= SNDRV_PCM_HW_PARAM_RATE;
+ } else if (params_rate(hw_params) * k_up < io->converted_rate) {
+ hw_param_interval(hw_params, SNDRV_PCM_HW_PARAM_RATE)->min =
+ (io->converted_rate + k_up - 1) / k_up;
+ hw_param_interval(hw_params, SNDRV_PCM_HW_PARAM_RATE)->max =
+ (io->converted_rate + k_up - 1) / k_up;
+ hw_params->cmask |= SNDRV_PCM_HW_PARAM_RATE;
+ }
+
+ /*
+ * TBD: Max SRC input and output rates also depend on number
+ * of channels and SRC unit:
+ * SRC1, SRC3 and SRC4 do not support more than 128kHz
+ * for 6 channel and 96kHz for 8 channel audio.
+ * Perhaps this function should return EINVAL if the input or
+ * the output rate exceeds the limitation.
+ */
+ }
}
return rsnd_dai_call(hw_params, io, substream, hw_params);