On 2023-08-11 8:21 PM, Pierre-Louis Bossart wrote:
On 8/11/23 11:48, Cezary Rojewski wrote:
To provide option for selecting different bit-per-sample than just the
maximum one, use the new format calculation mechanism.
Can you remind me what the issue is in selecting the maximum resolution?
Isn't it a good thing to select the maximum resolution when possible so
as to provide more headroom and prevent clipping? Usually we try to make
sure the resolution becomes limited when we reach the analog parts. I am
not sure I see a compelling reason to reduce the resolution on the host
side.
Maximum resolution is still the default, nothing changes there.
Moreover, new subformat options are not added to any driver apart from
the avs-driver.
The patchset provides _an option_ to change bits-per-sample. Right now
there's no option to do that so the hardware - here, SDxFMT and PPLCxFMT
- is not tested. We have enough recommended flows already. Frankly there
is one for SDxFMT for the APL-based platforms (or BXT-based if one
prefers that naming) present within snd_hda_intel and DSP drivers alike.
I am also not sure what this patch actually changes, given that the
firmware actually converts everything to the full 32-bit resolution.
The issue does not concern firmware, so we leave firmware out of the
discussion - this is purely about hardware capabilities.
I must be missing something on the problem statement.
Signed-off-by: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
---
sound/soc/sof/intel/hda-dai-ops.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/sound/soc/sof/intel/hda-dai-ops.c b/sound/soc/sof/intel/hda-dai-ops.c
index f3513796c189..00703999e91b 100644
--- a/sound/soc/sof/intel/hda-dai-ops.c
+++ b/sound/soc/sof/intel/hda-dai-ops.c
@@ -194,14 +194,15 @@ static unsigned int hda_calc_stream_format(struct snd_sof_dev *sdev,
struct snd_soc_dai *codec_dai = asoc_rtd_to_codec(rtd, 0);
unsigned int link_bps;
unsigned int format_val;
+ unsigned int bps;
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
link_bps = codec_dai->driver->playback.sig_bits;
else
link_bps = codec_dai->driver->capture.sig_bits;
+ bps = snd_hdac_stream_format_bps(params_format(params), SNDRV_PCM_SUBFORMAT_STD, link_bps);
I can't say I fully understand the difference between 'bps' and
'link_bps'. The naming is far from self-explanatory just by looking at
the code.
There's none. I just didn't reuse the 'link_bps' variable. I can reuse
it if you like.
- format_val = snd_hdac_calc_stream_format(params_rate(params), params_channels(params),
- params_format(params), link_bps, 0);
+ format_val = snd_hdac_stream_format(params_channels(params), bps, params_rate(params));
dev_dbg(sdev->dev, "format_val=%#x, rate=%d, ch=%d, format=%d\n", format_val,
params_rate(params), params_channels(params), params_format(params));
