This patch set contains the following patches
Andreas Pape (1):
ALSA: usb-audio: more tolerant packetsize
Daniel Girnus (1):
ALSA: usb-audio: avoid setting of sample rate multiple times on bus
sound/usb/endpoint.c | 4 ++--
sound/usb/pcm.c | 21 +++++++++++----------
2 files changed, 13 insertions(+), 12 deletions(-)
--
2.9.3
From: Daniel Girnus <[email protected]>
Some of userland applications call 'snd_pcm_hw_params()' and
'snd_pcm_hw_prepare()' sequentially, which means 'snd_pcm_hw_prepare()'
is called twice and the second 'snd_pcm_hw_prepare()' is called in
'SNDRV_PCM_STATE_PREPARED' state.
Some devices are not able to manage this and they will stop playback
if the sample rate will be configured several times over USB protocol.
V2: updated Changelog
Signed-off-by: Daniel Girnus <[email protected]>
Signed-off-by: Jens Lorenz <[email protected]>
Signed-off-by: Jiada Wang <[email protected]>
---
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
From: Andreas Pape <[email protected]>
since commit 57e6dae1087b ("ALSA: usb-audio: do not trust too-big
wMaxPacketSize values"), the expected packetsize is always limited
to nominal + 25%. It was discovered, that some devices have a much
higher jitter in used packetsizes than 25% which would result in BABBLE
condition and dropping of packets.
A better solution is so assume the jitter to be the nominal packetsize:
-one nearly empty packet followed by a almost 150% sized one.
V2: changed to assume max frequency is +50 of nominal packetsize.
Signed-off-by: Andreas Pape <[email protected]>
Signed-off-by: Jiada Wang <[email protected]>
---
sound/usb/endpoint.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index c470251..a2931f4 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -632,8 +632,8 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep,
ep->stride = frame_bits >> 3;
ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
- /* assume max. frequency is 25% higher than nominal */
- ep->freqmax = ep->freqn + (ep->freqn >> 2);
+ /* assume max. frequency is 50% higher than nominal */
+ ep->freqmax = ep->freqn + (ep->freqn >> 1);
/* Round up freqmax to nearest integer in order to calculate maximum
* packet size, which must represent a whole number of frames.
* This is accomplished by adding 0x0.ffff before converting the
--
2.9.3
On Tue, 06 Dec 2016 06:46:14 +0100,
Jiada Wang wrote:
>
> From: Andreas Pape <[email protected]>
>
> since commit 57e6dae1087b ("ALSA: usb-audio: do not trust too-big
> wMaxPacketSize values"), the expected packetsize is always limited
> to nominal + 25%. It was discovered, that some devices have a much
> higher jitter in used packetsizes than 25% which would result in BABBLE
> condition and dropping of packets.
> A better solution is so assume the jitter to be the nominal packetsize:
> -one nearly empty packet followed by a almost 150% sized one.
>
> V2: changed to assume max frequency is +50 of nominal packetsize.
Clemens, are you OK with this change?
Takashi
>
> Signed-off-by: Andreas Pape <[email protected]>
> Signed-off-by: Jiada Wang <[email protected]>
> ---
> sound/usb/endpoint.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
> index c470251..a2931f4 100644
> --- a/sound/usb/endpoint.c
> +++ b/sound/usb/endpoint.c
> @@ -632,8 +632,8 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep,
> ep->stride = frame_bits >> 3;
> ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
>
> - /* assume max. frequency is 25% higher than nominal */
> - ep->freqmax = ep->freqn + (ep->freqn >> 2);
> + /* assume max. frequency is 50% higher than nominal */
> + ep->freqmax = ep->freqn + (ep->freqn >> 1);
> /* Round up freqmax to nearest integer in order to calculate maximum
> * packet size, which must represent a whole number of frames.
> * This is accomplished by adding 0x0.ffff before converting the
> --
> 2.9.3
>
Jiada Wang wrote:
> since commit 57e6dae1087b ("ALSA: usb-audio: do not trust too-big
> wMaxPacketSize values"), the expected packetsize is always limited
> to nominal + 25%. It was discovered, that some devices
Android audio accessory
> have a much
> higher jitter in used packetsizes than 25% which would result in BABBLE
> condition and dropping of packets.
> A better solution is so assume the jitter to be the nominal packetsize:
> -one nearly empty packet followed by a almost 150% sized one.
>
> V2: changed to assume max frequency is +50 of nominal packetsize.
>
> Signed-off-by: Andreas Pape <[email protected]>
> Signed-off-by: Jiada Wang <[email protected]>
Acked-by: Clemens Ladisch <[email protected]>
> --- a/sound/usb/endpoint.c
> +++ b/sound/usb/endpoint.c
> @@ -632,8 +632,8 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep,
> ep->stride = frame_bits >> 3;
> ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
>
> - /* assume max. frequency is 25% higher than nominal */
> - ep->freqmax = ep->freqn + (ep->freqn >> 2);
> + /* assume max. frequency is 50% higher than nominal */
> + ep->freqmax = ep->freqn + (ep->freqn >> 1);
> /* Round up freqmax to nearest integer in order to calculate maximum
> * packet size, which must represent a whole number of frames.
> * This is accomplished by adding 0x0.ffff before converting the
On Tue, 06 Dec 2016 06:46:13 +0100,
Jiada Wang wrote:
>
> This patch set contains the following patches
>
> Andreas Pape (1):
> ALSA: usb-audio: more tolerant packetsize
>
> Daniel Girnus (1):
> ALSA: usb-audio: avoid setting of sample rate multiple times on bus
Applied both patches, thanks.
Takashi