Re: [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus
On Dec 5 2016 16:32, Jiada Wang wrote: Hi Sakamoto On 11/30/2016 02:45 AM, Takashi Sakamoto wrote: Hi Jiada, I don't oppose this patch. Nevertheless, your description is not necessarily correct. On Nov 30 2016 16:59, Jiada Wang wrote: From: Daniel Girnus ALSA usually calls the prepare function twice before starting the playback: 1. On hw_params call from userland and 2. internally when starting the stream. ALSA PCM core in kernel land doesn't perform like this. In alsa-lib, 'snd_pcm_hw_params()' calls 'snd_pcm_hw_params_internal()' and 'snd_pcm_prepare()' sequentially. http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/pcm/pcm.c;h=cd87bc759ded95953e332b7e8d56b0f2d5b4185d;hb=HEAD#l853 In system call level (e.g. see by strace(1)), this looks like two ioctl(2)s with 'SNDRV_PCM_IOCTL_HW_PARAMS' and 'SNDRV_PCM_IOCTL_PREPARE'. Well, when applications are written to execute 'snd_pcm_hw_params()' and 'snd_pcm_hw_prepare()' sequentially, additional ioctl(2) with 'SNDRV_PCM_IOCTL_PREPARE' appears. PulseAudio is this kind of application. I indicated the useless in 2014, but it still remains: https://lists.freedesktop.org/archives/pulseaudio-discuss/2014-January/019773.html You have the misunderstanding due to a nature of alsa-lib and tendency of major applications, from my point of view. Thanks for your indication, so because some of userland applications call 'snd_pcm_hw_params()' and 'snd_pcm_hw_prepare()' sequentially, means the second 'SNDRV_PCM_IOCTL_PREPARE' be called in 'SNDRV_PCM_STATE_PREPARED' state, Exactly. Furthermore, ALSA PCM core has no code to call .prepare() in contexts unrelated to SNDRV_PCM_IOCTL_PREPARE. some devices are unable to manage this and stop working. I will update Changelog in v2 Patchset. Regards Takashi Sakamoto
Re: [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus
Hi Sakamoto
On 11/30/2016 02:45 AM, Takashi Sakamoto wrote:
Hi Jiada,
I don't oppose this patch. Nevertheless, your description is not
necessarily correct.
On Nov 30 2016 16:59, Jiada Wang wrote:
From: Daniel Girnus
ALSA usually calls the prepare function twice before starting the
playback:
1. On hw_params call from userland and
2. internally when starting the stream.
ALSA PCM core in kernel land doesn't perform like this.
In alsa-lib, 'snd_pcm_hw_params()' calls
'snd_pcm_hw_params_internal()' and 'snd_pcm_prepare()' sequentially.
http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/pcm/pcm.c;h=cd87bc759ded95953e332b7e8d56b0f2d5b4185d;hb=HEAD#l853
In system call level (e.g. see by strace(1)), this looks like two
ioctl(2)s with 'SNDRV_PCM_IOCTL_HW_PARAMS' and 'SNDRV_PCM_IOCTL_PREPARE'.
Well, when applications are written to execute 'snd_pcm_hw_params()'
and 'snd_pcm_hw_prepare()' sequentially, additional ioctl(2) with
'SNDRV_PCM_IOCTL_PREPARE' appears. PulseAudio is this kind of
application. I indicated the useless in 2014, but it still remains:
https://lists.freedesktop.org/archives/pulseaudio-discuss/2014-January/019773.html
You have the misunderstanding due to a nature of alsa-lib and tendency
of major applications, from my point of view.
Thanks for your indication, so because some of userland applications
call 'snd_pcm_hw_params()' and
'snd_pcm_hw_prepare()' sequentially, means the second
'SNDRV_PCM_IOCTL_PREPARE' be called in 'SNDRV_PCM_STATE_PREPARED' state,
some devices are unable to manage this and stop working.
I will update Changelog in v2 Patchset.
Thanks,
Jiada
Some device are not able to manage this and they will stop playback
if the sample rate will be configured several times over USB protocol.
Signed-off-by: Jens Lorenz
Signed-off-by: Jiada Wang
---
sound/usb/pcm.c | 21 +++--
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 44d178e..a522c9a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -806,17 +806,18 @@ static int snd_usb_pcm_prepare(struct
snd_pcm_substream *substream)
if (ret < 0)
goto unlock;
-iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
-alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
-ret = snd_usb_init_sample_rate(subs->stream->chip,
- subs->cur_audiofmt->iface,
- alts,
- subs->cur_audiofmt,
- subs->cur_rate);
-if (ret < 0)
-goto unlock;
-
if (subs->need_setup_ep) {
+
+iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
+alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
+ret = snd_usb_init_sample_rate(subs->stream->chip,
+ subs->cur_audiofmt->iface,
+ alts,
+ subs->cur_audiofmt,
+ subs->cur_rate);
+if (ret < 0)
+goto unlock;
+
ret = configure_endpoint(subs);
if (ret < 0)
goto unlock;
Regards
Takashi Sakamoto
Re: [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus
Hi Takashi
On 11/30/2016 05:51 PM, Takashi Iwai wrote:
On Wed, 30 Nov 2016 08:59:22 +0100,
Jiada Wang wrote:
From: Daniel Girnus
ALSA usually calls the prepare function twice before starting the playback:
1. On hw_params call from userland and
2. internally when starting the stream.
Some device are not able to manage this and they will stop playback
if the sample rate will be configured several times over USB protocol.
Signed-off-by: Jens Lorenz
Signed-off-by: Jiada Wang
The sign-off from Daniel seems missing?
The code change looks OK, but it'd be nice to mention in the changelog
that, after this patch, snd_usb_init_sample_rate() is still called
properly whenever the parameter is changed since ep->need_setup_ep is
set in snd_hsb_hw_params().
I will add missing sign-off and related information in changelog in v2
Thanks,
Jiada
thanks,
Takashi
---
sound/usb/pcm.c | 21 +++--
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 44d178e..a522c9a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -806,17 +806,18 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream
*substream)
if (ret < 0)
goto unlock;
- iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
- alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
- ret = snd_usb_init_sample_rate(subs->stream->chip,
- subs->cur_audiofmt->iface,
- alts,
- subs->cur_audiofmt,
- subs->cur_rate);
- if (ret < 0)
- goto unlock;
-
if (subs->need_setup_ep) {
+
+ iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
+ alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
+ ret = snd_usb_init_sample_rate(subs->stream->chip,
+ subs->cur_audiofmt->iface,
+ alts,
+ subs->cur_audiofmt,
+ subs->cur_rate);
+ if (ret < 0)
+ goto unlock;
+
ret = configure_endpoint(subs);
if (ret < 0)
goto unlock;
--
2.9.3
Re: [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus
On Nov 30 2016 19:45, Takashi Sakamoto wrote: Hi Jiada, I don't oppose this patch. Nevertheless, your description is not necessarily correct. On Nov 30 2016 16:59, Jiada Wang wrote: From: Daniel Girnus ALSA usually calls the prepare function twice before starting the playback: 1. On hw_params call from userland and 2. internally when starting the stream. ALSA PCM core in kernel land doesn't perform like this. In alsa-lib, 'snd_pcm_hw_params()' calls 'snd_pcm_hw_params_internal()' and 'snd_pcm_prepare()' sequentially. http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/pcm/pcm.c;h=cd87bc759ded95953e332b7e8d56b0f2d5b4185d;hb=HEAD#l853 In system call level (e.g. see by strace(1)), this looks like two ioctl(2)s with 'SNDRV_PCM_IOCTL_HW_PARAMS' and 'SNDRV_PCM_IOCTL_PREPARE'. Well, when applications are written to execute 'snd_pcm_hw_params()' and 'snd_pcm_hw_prepare()' sequentially, additional ioctl(2) with 'SNDRV_PCM_IOCTL_PREPARE' appears. PulseAudio is this kind of application. I indicated the useless in 2014, but it still remains: https://lists.freedesktop.org/archives/pulseaudio-discuss/2014-January/019773.html You have the misunderstanding due to a nature of alsa-lib and tendency of major applications, from my point of view. So here you should mention that current USB Audio device class driver somewhat ignores state machine of ALSA PCM runtime. In ALSA PCM core, state of the runtime is described in 'struct snd_pcm_runtime.status.state' with macros of 'SNDRV_PCM_STATE_XXX'. Applications are allowed to handle the runtime according to the state. In your issue, the driver is programmed ignoring a case that double calls of snd_pcm_prepare(), in short, ioctl(PREPARE) is called in 'PREPARED' state. This is not only an issue for snd-usb-audio, but also for snd-usb-hiface. http://mailman.alsa-project.org/pipermail/alsa-devel/2016-November/115174.html For these issue, I have no patch proposals because I have few test devices, sorry. Regards Takashi Sakamoto
Re: [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus
Hi Jiada,
I don't oppose this patch. Nevertheless, your description is not
necessarily correct.
On Nov 30 2016 16:59, Jiada Wang wrote:
From: Daniel Girnus
ALSA usually calls the prepare function twice before starting the playback:
1. On hw_params call from userland and
2. internally when starting the stream.
ALSA PCM core in kernel land doesn't perform like this.
In alsa-lib, 'snd_pcm_hw_params()' calls 'snd_pcm_hw_params_internal()'
and 'snd_pcm_prepare()' sequentially.
http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/pcm/pcm.c;h=cd87bc759ded95953e332b7e8d56b0f2d5b4185d;hb=HEAD#l853
In system call level (e.g. see by strace(1)), this looks like two
ioctl(2)s with 'SNDRV_PCM_IOCTL_HW_PARAMS' and 'SNDRV_PCM_IOCTL_PREPARE'.
Well, when applications are written to execute 'snd_pcm_hw_params()' and
'snd_pcm_hw_prepare()' sequentially, additional ioctl(2) with
'SNDRV_PCM_IOCTL_PREPARE' appears. PulseAudio is this kind of
application. I indicated the useless in 2014, but it still remains:
https://lists.freedesktop.org/archives/pulseaudio-discuss/2014-January/019773.html
You have the misunderstanding due to a nature of alsa-lib and tendency
of major applications, from my point of view.
Some device are not able to manage this and they will stop playback
if the sample rate will be configured several times over USB protocol.
Signed-off-by: Jens Lorenz
Signed-off-by: Jiada Wang
---
sound/usb/pcm.c | 21 +++--
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 44d178e..a522c9a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -806,17 +806,18 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream
*substream)
if (ret < 0)
goto unlock;
- iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
- alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
- ret = snd_usb_init_sample_rate(subs->stream->chip,
- subs->cur_audiofmt->iface,
- alts,
- subs->cur_audiofmt,
- subs->cur_rate);
- if (ret < 0)
- goto unlock;
-
if (subs->need_setup_ep) {
+
+ iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
+ alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
+ ret = snd_usb_init_sample_rate(subs->stream->chip,
+ subs->cur_audiofmt->iface,
+ alts,
+ subs->cur_audiofmt,
+ subs->cur_rate);
+ if (ret < 0)
+ goto unlock;
+
ret = configure_endpoint(subs);
if (ret < 0)
goto unlock;
Regards
Takashi Sakamoto
Re: [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus
On Wed, 30 Nov 2016 08:59:22 +0100,
Jiada Wang wrote:
>
> From: Daniel Girnus
>
> ALSA usually calls the prepare function twice before starting the playback:
> 1. On hw_params call from userland and
> 2. internally when starting the stream.
> Some device are not able to manage this and they will stop playback
> if the sample rate will be configured several times over USB protocol.
>
> Signed-off-by: Jens Lorenz
> Signed-off-by: Jiada Wang
The sign-off from Daniel seems missing?
The code change looks OK, but it'd be nice to mention in the changelog
that, after this patch, snd_usb_init_sample_rate() is still called
properly whenever the parameter is changed since ep->need_setup_ep is
set in snd_hsb_hw_params().
thanks,
Takashi
> ---
> sound/usb/pcm.c | 21 +++--
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
> index 44d178e..a522c9a 100644
> --- a/sound/usb/pcm.c
> +++ b/sound/usb/pcm.c
> @@ -806,17 +806,18 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream
> *substream)
> if (ret < 0)
> goto unlock;
>
> - iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
> - alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
> - ret = snd_usb_init_sample_rate(subs->stream->chip,
> -subs->cur_audiofmt->iface,
> -alts,
> -subs->cur_audiofmt,
> -subs->cur_rate);
> - if (ret < 0)
> - goto unlock;
> -
> if (subs->need_setup_ep) {
> +
> + iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
> + alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
> + ret = snd_usb_init_sample_rate(subs->stream->chip,
> +subs->cur_audiofmt->iface,
> +alts,
> +subs->cur_audiofmt,
> +subs->cur_rate);
> + if (ret < 0)
> + goto unlock;
> +
> ret = configure_endpoint(subs);
> if (ret < 0)
> goto unlock;
> --
> 2.9.3
>
>
[PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus
From: Daniel Girnus
ALSA usually calls the prepare function twice before starting the playback:
1. On hw_params call from userland and
2. internally when starting the stream.
Some device are not able to manage this and they will stop playback
if the sample rate will be configured several times over USB protocol.
Signed-off-by: Jens Lorenz
Signed-off-by: Jiada Wang
---
sound/usb/pcm.c | 21 +++--
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 44d178e..a522c9a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -806,17 +806,18 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream
*substream)
if (ret < 0)
goto unlock;
- iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
- alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
- ret = snd_usb_init_sample_rate(subs->stream->chip,
- subs->cur_audiofmt->iface,
- alts,
- subs->cur_audiofmt,
- subs->cur_rate);
- if (ret < 0)
- goto unlock;
-
if (subs->need_setup_ep) {
+
+ iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
+ alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
+ ret = snd_usb_init_sample_rate(subs->stream->chip,
+ subs->cur_audiofmt->iface,
+ alts,
+ subs->cur_audiofmt,
+ subs->cur_rate);
+ if (ret < 0)
+ goto unlock;
+
ret = configure_endpoint(subs);
if (ret < 0)
goto unlock;
--
2.9.3
