On 02/07/2017 11:09 AM, Takashi Iwai wrote:
On Tue, 07 Feb 2017 17:48:59 +0100, Pierre-Louis Bossart wrote:
On 02/07/2017 07:11 AM, Takashi Iwai wrote:
Now we support S16 PCM format in addition. For this, we need to set packet_mode=1 in AUD_CONFIG register.
While I think of it, there is a hidden benefit here. If this mode works, then most likely we can push IEC61937 data formatted as S16 PCM directly. For passthrough we needed to left-shit the data, if this mode does what it says it should make some people happy. The U,C,V should not be added in the data stream however (as done by the hdmi: plugin), there is a separate register to program then.
Yes, embedding the raw IEC data stream is an interesting move, indeed. But right now I'm not sure which configuration allows that operation mode.
In my patch, I just played with AUD_CONFIG packet_mode bit. Maybe other fields (fmt, flat, user_bit) may play some relevant role?
Also, Channel Status 0 register have lots of uninitialized fields. Some of ch0 bits are carried from AES status bits, but many are left untouched.
I think there are two registers for a total for 40bits that can store what will go in the channel status bits. The remaining bits to 192 are not supported. That's an optimization that existed even before I joined, no idea why they tried to save 152 bits...
In most cases you don't even need to configure stuff, the receivers don't trust all these bits and will determine PCM/IEC61937 encoding based on the actual payload, not the control bits (with the side effect that switching between PCM/IC61937 takes time)
thanks,
Takashi
Signed-off-by: Takashi Iwai tiwai@suse.de
sound/x86/intel_hdmi_audio.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/sound/x86/intel_hdmi_audio.c b/sound/x86/intel_hdmi_audio.c index a0401476cd93..5697552f489a 100644 --- a/sound/x86/intel_hdmi_audio.c +++ b/sound/x86/intel_hdmi_audio.c @@ -136,7 +136,8 @@ static const struct snd_pcm_hardware had_pcm_hardware = { SNDRV_PCM_INFO_MMAP| SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BATCH),
- .formats = (SNDRV_PCM_FMTBIT_S24_LE |
- .formats = (SNDRV_PCM_FMTBIT_S16_LE |
SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE),@@ -308,12 +309,10 @@ static int had_prog_status_reg(struct snd_pcm_substream *substream, AUD_CH_STATUS_0, ch_stat0.regval); switch (substream->runtime->format) { -#if 0 /* FIXME: not supported yet */ case SNDRV_PCM_FORMAT_S16_LE: ch_stat1.regx.max_wrd_len = MAX_SMPL_WIDTH_20; ch_stat1.regx.wrd_len = SMPL_WIDTH_16BITS; break; -#endif case SNDRV_PCM_FORMAT_S24_LE: case SNDRV_PCM_FORMAT_S32_LE: ch_stat1.regx.max_wrd_len = MAX_SMPL_WIDTH_24; @@ -354,6 +353,9 @@ static int had_init_audio_ctrl(struct snd_pcm_substream *substream, else cfg_val.regx.layout = LAYOUT1;
- if (substream->runtime->format == SNDRV_PCM_FORMAT_S16_LE)
cfg_val.regx.packet_mode = 1;- if (substream->runtime->format == SNDRV_PCM_FORMAT_S32_LE) cfg_val.regx.left_align = 1;