| Message ID | a7b69fb075b0ae993846cfb65abb20ecab5c9805.1442572860.git.jsarha@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Sep 18, 2015 at 02:06:39PM +0300, Jyri Sarha wrote: > Add IEC958 channel status helper that gets the audio properties from > snd_pcm_hw_params instead of snd_pcm_runtime. This is needed to > produce the channel status bits already in audio stream configuration > phase. > > Signed-off-by: Jyri Sarha <jsarha@ti.com> > --- > include/sound/pcm_iec958.h | 2 ++ > sound/core/pcm_iec958.c | 52 +++++++++++++++++++++++++++++++--------------- This is core ALSA code, you need to CC Takashi (added him, not cutting context). > 2 files changed, 37 insertions(+), 17 deletions(-) > > diff --git a/include/sound/pcm_iec958.h b/include/sound/pcm_iec958.h > index 0eed397..36f023a 100644 > --- a/include/sound/pcm_iec958.h > +++ b/include/sound/pcm_iec958.h > @@ -6,4 +6,6 @@ > int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, > size_t len); > > +int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params, > + u8 *cs, size_t len); > #endif > diff --git a/sound/core/pcm_iec958.c b/sound/core/pcm_iec958.c > index 36b2d7a..c9f8b66 100644 > --- a/sound/core/pcm_iec958.c > +++ b/sound/core/pcm_iec958.c > @@ -9,30 +9,18 @@ > #include <linux/types.h> > #include <sound/asoundef.h> > #include <sound/pcm.h> > +#include <sound/pcm_params.h> > #include <sound/pcm_iec958.h> > > -/** > - * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status > - * @runtime: pcm runtime structure with ->rate filled in > - * @cs: channel status buffer, at least four bytes > - * @len: length of channel status buffer > - * > - * Create the consumer format channel status data in @cs of maximum size > - * @len corresponding to the parameters of the PCM runtime @runtime. > - * > - * Drivers may wish to tweak the contents of the buffer after creation. > - * > - * Returns: length of buffer, or negative error code if something failed. > - */ > -int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, > - size_t len) > +static int create_iec958_consumer(uint rate, uint sample_width, > + u8 *cs, size_t len) > { > unsigned int fs, ws; > > if (len < 4) > return -EINVAL; > > - switch (runtime->rate) { > + switch (rate) { > case 32000: > fs = IEC958_AES3_CON_FS_32000; > break; > @@ -59,7 +47,7 @@ int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, > } > > if (len > 4) { > - switch (snd_pcm_format_width(runtime->format)) { > + switch (sample_width) { > case 16: > ws = IEC958_AES4_CON_WORDLEN_20_16; > break; > @@ -92,4 +80,34 @@ int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, > > return len; > } > + > +/** > + * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status > + * @runtime: pcm runtime structure with ->rate filled in > + * @cs: channel status buffer, at least four bytes > + * @len: length of channel status buffer > + * > + * Create the consumer format channel status data in @cs of maximum size > + * @len corresponding to the parameters of the PCM runtime @runtime. > + * > + * Drivers may wish to tweak the contents of the buffer after creation. > + * > + * Returns: length of buffer, or negative error code if something failed. > + */ > +int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, > + size_t len) > +{ > + return create_iec958_consumer(runtime->rate, > + snd_pcm_format_width(runtime->format), > + cs, len); > +} > EXPORT_SYMBOL(snd_pcm_create_iec958_consumer); > + > + > +int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params, > + u8 *cs, size_t len) > +{ > + return create_iec958_consumer(params_rate(params), params_width(params), > + cs, len); > +} > +EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params); > -- > 1.9.1 > >
On Fri, Sep 18, 2015 at 02:06:39PM +0300, Jyri Sarha wrote: > Add IEC958 channel status helper that gets the audio properties from > snd_pcm_hw_params instead of snd_pcm_runtime. This is needed to > produce the channel status bits already in audio stream configuration > phase. What is the reason for doing this early? ALSA documentation (which may be out of date) says that the hw_params callback can be called multiple times during stream setup. Do we want to be repeatedly programming the HDMI infoframe with different settings, potentially confusing the attached device, or would it be better to do it slightly later (in the prepare callback) after the parameters have been fully negotiated?
On 09/21/15 12:37, Russell King - ARM Linux wrote: > On Fri, Sep 18, 2015 at 02:06:39PM +0300, Jyri Sarha wrote: >> Add IEC958 channel status helper that gets the audio properties from >> snd_pcm_hw_params instead of snd_pcm_runtime. This is needed to >> produce the channel status bits already in audio stream configuration >> phase. > > What is the reason for doing this early? > After some thinking, there is no good reason. It makes the codec bit more complicated, but that is not a good reason. I'll change that and use the prepare callback. This patch can be dropped. > ALSA documentation (which may be out of date) says that the hw_params > callback can be called multiple times during stream setup. Do we want > to be repeatedly programming the HDMI infoframe with different settings, > potentially confusing the attached device, or would it be better to do > it slightly later (in the prepare callback) after the parameters have > been fully negotiated? > If it is possible that hw_params() can be called multiple times, at least it does not happen very often. I wonder if it would ever happen again after a successful hw_params() call. But there is no downside in using prepare callback. I was just too much following the way ASoC codecs usually do the thing by writing everything to iron as the callbacks come in. Best regards, Jyri
Jyri Sarha wrote: > On 09/21/15 12:37, Russell King - ARM Linux wrote: >> ALSA documentation (which may be out of date) says that the hw_params >> callback can be called multiple times during stream setup. Do we want >> to be repeatedly programming the HDMI infoframe with different settings, >> potentially confusing the attached device, or would it be better to do >> it slightly later (in the prepare callback) after the parameters have >> been fully negotiated? > > If it is possible that hw_params() can be called multiple times, at > least it does not happen very often. I wonder if it would ever happen > again after a successful hw_params() call. It is certainly allowed, and it happens regularly when using OSS emulation. AFAIK PulseAudio does something similar when enumerating devices. > But there is no downside in using prepare callback. The prepare callback also can be called multiple times. This certainly happens when the stream is stopped/restarted multiple times. If something does not need to be done again when a stream is restarted, then it should be done in the hw_params callback. Regards, Clemens
On 09/21/15 18:08, Clemens Ladisch wrote: >> >But there is no downside in using prepare callback. > The prepare callback also can be called multiple times. This certainly > happens when the stream is stopped/restarted multiple times. > > If something does not need to be done again when a stream is restarted, > then it should be done in the hw_params callback. Oh, forgot about that. This would suggest to keep the stream header configuration in the hw_params(). Thanks, Jyri
diff --git a/include/sound/pcm_iec958.h b/include/sound/pcm_iec958.h index 0eed397..36f023a 100644 --- a/include/sound/pcm_iec958.h +++ b/include/sound/pcm_iec958.h @@ -6,4 +6,6 @@ int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, size_t len); +int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params, + u8 *cs, size_t len); #endif diff --git a/sound/core/pcm_iec958.c b/sound/core/pcm_iec958.c index 36b2d7a..c9f8b66 100644 --- a/sound/core/pcm_iec958.c +++ b/sound/core/pcm_iec958.c @@ -9,30 +9,18 @@ #include <linux/types.h> #include <sound/asoundef.h> #include <sound/pcm.h> +#include <sound/pcm_params.h> #include <sound/pcm_iec958.h> -/** - * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status - * @runtime: pcm runtime structure with ->rate filled in - * @cs: channel status buffer, at least four bytes - * @len: length of channel status buffer - * - * Create the consumer format channel status data in @cs of maximum size - * @len corresponding to the parameters of the PCM runtime @runtime. - * - * Drivers may wish to tweak the contents of the buffer after creation. - * - * Returns: length of buffer, or negative error code if something failed. - */ -int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, - size_t len) +static int create_iec958_consumer(uint rate, uint sample_width, + u8 *cs, size_t len) { unsigned int fs, ws; if (len < 4) return -EINVAL; - switch (runtime->rate) { + switch (rate) { case 32000: fs = IEC958_AES3_CON_FS_32000; break; @@ -59,7 +47,7 @@ int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, } if (len > 4) { - switch (snd_pcm_format_width(runtime->format)) { + switch (sample_width) { case 16: ws = IEC958_AES4_CON_WORDLEN_20_16; break; @@ -92,4 +80,34 @@ int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, return len; } + +/** + * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status + * @runtime: pcm runtime structure with ->rate filled in + * @cs: channel status buffer, at least four bytes + * @len: length of channel status buffer + * + * Create the consumer format channel status data in @cs of maximum size + * @len corresponding to the parameters of the PCM runtime @runtime. + * + * Drivers may wish to tweak the contents of the buffer after creation. + * + * Returns: length of buffer, or negative error code if something failed. + */ +int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, + size_t len) +{ + return create_iec958_consumer(runtime->rate, + snd_pcm_format_width(runtime->format), + cs, len); +} EXPORT_SYMBOL(snd_pcm_create_iec958_consumer); + + +int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params, + u8 *cs, size_t len) +{ + return create_iec958_consumer(params_rate(params), params_width(params), + cs, len); +} +EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params);
Add IEC958 channel status helper that gets the audio properties from snd_pcm_hw_params instead of snd_pcm_runtime. This is needed to produce the channel status bits already in audio stream configuration phase. Signed-off-by: Jyri Sarha <jsarha@ti.com> --- include/sound/pcm_iec958.h | 2 ++ sound/core/pcm_iec958.c | 52 +++++++++++++++++++++++++++++++--------------- 2 files changed, 37 insertions(+), 17 deletions(-)