Re: [PATCH 1/1] Updated negative return values for documentation update.

Dear Tiwai san,

First of all, thank you very much all those years you contributed on ALSA.

Couple of days ago I emailed you over updating remark fields. The purpose of edit was providing more error and meaning to application engineers.

For example, when snd_pcm_writei returned -EIO, application engineer didn’t understand what it means because the documentation didn’t include -EIO comment.

Would you please let me know if I need to do something to apply these changes? I’m very new to linux community, and I thought create a patch and email to relevant recipients. However, it looks like I’m missing something here. :)

FYI, I have not changed any code.

Thank you.

Best regards, CJ Lee

2020. 5. 12. 오후 6:05, changjoon.lee@lge.com 작성:

From: ChangJoon Lee changjoon.lee@lge.com

Signed-off-by: ChangJoon Lee changjoon.lee@lge.com

src/pcm/pcm.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 54 insertions(+), 3 deletions(-)

diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c index 1064044c..b53797a6 100644 --- a/src/pcm/pcm.c +++ b/src/pcm/pcm.c @@ -820,6 +820,7 @@ int snd_pcm_nonblock(snd_pcm_t *pcm, int nonblock)

• \param sig Signal to raise: < 0 disable, 0 default (SIGIO)
• \param pid Process ID to signal: 0 current
• \return 0 on success otherwise a negative error code

• • \return -ENOSYS Async is not supported on this PCM

• A signal is raised every period.

*/ @@ -850,6 +851,7 @@ int snd_pcm_async(snd_pcm_t *pcm, int sig, pid_t pid)

• \param pcm PCM handle
• \param info Information container
• \return 0 on success otherwise a negative error code

• • \return -ENOSYS Info is not supported on this PCM

*/ int snd_pcm_info(snd_pcm_t *pcm, snd_pcm_info_t *info) { @@ -867,6 +869,7 @@ int snd_pcm_info(snd_pcm_t *pcm, snd_pcm_info_t *info)

• \param pcm PCM handle
• \param params Configuration space definition container
• \return 0 on success otherwise a negative error code

• • \return -EBADFD PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)

*/ int snd_pcm_hw_params_current(snd_pcm_t *pcm, snd_pcm_hw_params_t *params) { @@ -933,6 +936,7 @@ int snd_pcm_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t *params) /** \brief Remove PCM hardware configuration and free associated resources

• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \return -ENOSYS Hw_free is not supported on this PCM

*/ int snd_pcm_hw_free(snd_pcm_t *pcm) { @@ -960,7 +964,9 @@ int snd_pcm_hw_free(snd_pcm_t *pcm)

• \param pcm PCM handle
• \param params Configuration container
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EINVAL Incorrect parameter, avail_min cannot be 0

• The software parameters can be changed at any time.
• The hardware parameters cannot be changed when the stream is
• running (active).

@@ -1017,6 +1023,7 @@ int snd_pcm_sw_params(snd_pcm_t *pcm, snd_pcm_sw_params_t *params)

• \param pcm PCM handle
• \param status Status container
• \return 0 on success otherwise a negative error code

• • \return -ENOSYS Status is not supported on this PCM

• The function is thread-safe when built with the proper option.

*/ @@ -1060,7 +1067,8 @@ snd_pcm_state_t snd_pcm_state(snd_pcm_t *pcm)

• \brief (DEPRECATED) Synchronize stream position with hardware
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)

• Note this function does not update the actual r/w pointer
• for applications. The function #snd_pcm_avail_update()
• have to be called before any mmap begin+commit operation.

@@ -1089,6 +1097,7 @@ int snd_pcm_hwsync(snd_pcm_t *pcm)

• \param pcm PCM handle
• \param delayp Returned delay in frames
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)

• For playback the delay is defined as the time that a frame that is written
• to the PCM stream shortly after this call will take to be actually

@@ -1133,6 +1142,7 @@ int snd_pcm_delay(snd_pcm_t *pcm, snd_pcm_sframes_t *delayp)

• \brief Resume from suspend, no samples are lost
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)

• \retval -EAGAIN resume can't be proceed immediately (audio hardware is probably still suspended)
• \retval -ENOSYS hardware doesn't support this feature

@@ -1166,6 +1176,8 @@ int snd_pcm_resume(snd_pcm_t *pcm)

• \param avail Number of available frames when timestamp was grabbed
• \param tstamp Hi-res timestamp
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -ENOSYS Hi-res timestamp is not supported on this system.

• Note this function does not update the actual r/w pointer
• for applications.

@@ -1194,6 +1206,9 @@ int snd_pcm_htimestamp(snd_pcm_t *pcm, snd_pcm_uframes_t *avail, snd_htimestamp_

• \brief Prepare PCM for use
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -ENOSYS Prepare is not supported on this PCM
• • \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_DISCONNECTED)

• The function is thread-safe when built with the proper option.

*/ @@ -1222,6 +1237,8 @@ int snd_pcm_prepare(snd_pcm_t *pcm)

• \brief Reset PCM position
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -ENOSYS Reset is not supported on this PCM

• Reduce PCM delay to 0.

@@ -1249,6 +1266,8 @@ int snd_pcm_reset(snd_pcm_t *pcm)

• \brief Start a PCM
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED)

• The function is thread-safe when built with the proper option.

*/ @@ -1274,6 +1293,8 @@ int snd_pcm_start(snd_pcm_t *pcm)

• \brief Stop a PCM dropping pending frames
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (Should be PREPARED,RUNNING,XRUN,PAUSED,DRAINING,SETUP or SUSPENDED)

• This function stops the PCM <i>immediately</i>.
• The pending samples on the buffer are ignored.

@@ -1309,7 +1330,10 @@ int snd_pcm_drop(snd_pcm_t *pcm)

• \brief Stop a PCM preserving pending frames
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (Should be PREPARED,RUNNING,XRUN,PAUSED or DRAINING,SETUP or SUSPENDED)

• \retval -ESTRPIPE a suspend event occurred

• • \retval -ENOSYS Drain is not supported on this PCM

• For playback wait for all pending frames to be played and then stop
• the PCM.

@@ -1345,6 +1369,10 @@ int snd_pcm_drain(snd_pcm_t *pcm)

• \param pcm PCM handle
• \param enable 0 = resume, 1 = pause
• \return 0 on success otherwise a negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (Should be PREPARED,RUNNING,XRUN,PAUSED or DRAINING)
• • \retval -ESTRPIPE a suspend event occurred
• • \retval -ENOSYS Pause is not supported on this PCM

• Note that this function works only on the hardware which supports
• pause feature. You can check it via \link ::snd_pcm_hw_params_can_pause() \endlink

@@ -1377,6 +1405,10 @@ int snd_pcm_pause(snd_pcm_t *pcm, int enable)

• \brief Get safe count of frames which can be rewinded
• \param pcm PCM handle
• \return a positive number of frames or negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (Should be PREPARED,RUNNING,XRUN,PAUSED or DRAINING)
• • \retval -ESTRPIPE a suspend event occurred
• • \retval -ENOSYS Rewindable is not supported on this PCM

• Note: The snd_pcm_rewind() can accept bigger value than returned
• by this function. But it is not guaranteed that output stream

@@ -1412,6 +1444,9 @@ snd_pcm_sframes_t snd_pcm_rewindable(snd_pcm_t *pcm)

• \param frames wanted displacement in frames
• \return a positive number for actual displacement otherwise a
• negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (Should be PREPARED,RUNNING,XRUN,PAUSED or DRAINING)
• • \retval -ENOSYS Rewind is not supported on this PCM

• The function is thread-safe when built with the proper option.

*/ @@ -1443,6 +1478,9 @@ snd_pcm_sframes_t snd_pcm_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

• \brief Get safe count of frames which can be forwarded
• \param pcm PCM handle
• \return a positive number of frames or negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (Should be PREPARED,RUNNING,XRUN,PAUSED or DRAINING)
• • \retval -ENOSYS Forwardable is not supported on this PCM

• Note: The snd_pcm_forward() can accept bigger value than returned
• by this function. But it is not guaranteed that output stream

@@ -1478,6 +1516,9 @@ snd_pcm_sframes_t snd_pcm_forwardable(snd_pcm_t *pcm)

• \param frames wanted skip in frames
• \return a positive number for actual skip otherwise a negative error code
• \retval 0 means no action

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EBADFD PCM is not in the right state (Should be PREPARED,RUNNING,XRUN,PAUSED or DRAINING)
• • \retval -ENOSYS Forward is not supported on this PCM

• The function is thread-safe when built with the proper option.

*/ @@ -1517,6 +1558,8 @@ use_default_symbol_version(__snd_pcm_forward, snd_pcm_forward, ALSA_0.9.0rc8);

• \param size frames to be written
• \return a positive number of frames actually written otherwise a
• negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EINVAL Access type is not Interleave type.

• \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
• \retval -EPIPE an underrun occurred
• \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)

@@ -1556,6 +1599,8 @@ snd_pcm_sframes_t snd_pcm_writei(snd_pcm_t *pcm, const void *buffer, snd_pcm_ufr

• \param size frames to be written
• \return a positive number of frames actually written otherwise a
• negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EINVAL Access type is not Non-Interleave type.

• \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
• \retval -EPIPE an underrun occurred
• \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)

@@ -1595,6 +1640,8 @@ snd_pcm_sframes_t snd_pcm_writen(snd_pcm_t *pcm, void **bufs, snd_pcm_uframes_t

• \param size frames to be read
• \return a positive number of frames actually read otherwise a
• negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EINVAL Access type is not Interleave type.

• \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
• \retval -EPIPE an overrun occurred
• \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)

@@ -1634,6 +1681,8 @@ snd_pcm_sframes_t snd_pcm_readi(snd_pcm_t *pcm, void *buffer, snd_pcm_uframes_t

• \param size frames to be read
• \return a positive number of frames actually read otherwise a
• negative error code

• • \retval -EIO PCM has not been setup (PCM isn't configured yet, or lifecycle of PCM has been ended)
• • \retval -EINVAL Access type is not Non-Interleave type.

• \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
• \retval -EPIPE an overrun occurred
• \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)

@@ -1669,8 +1718,9 @@ snd_pcm_sframes_t snd_pcm_readn(snd_pcm_t *pcm, void **bufs, snd_pcm_uframes_t s /**

• \brief Link two PCMs
• \param pcm1 first PCM handle

• • \param pcm2 first PCM handle

• • \param pcm2 second PCM handle

• \return 0 on success otherwise a negative error code

• • \retval -ENOSYS Link is not supported on pcm1

• The two PCMs will start/stop/prepare in sync.

*/ @@ -1691,6 +1741,7 @@ int snd_pcm_link(snd_pcm_t *pcm1, snd_pcm_t *pcm2)

• \brief Remove a PCM from a linked group
• \param pcm PCM handle
• \return 0 on success otherwise a negative error code

• • \retval -ENOSYS Unlink is not supported on this PCM.

*/ int snd_pcm_unlink(snd_pcm_t *pcm) { -- 2.26.2