diff options
Diffstat (limited to 'SOURCES/ALSA:-usb-audio:-Split-endpoint-setups-for-hw_params-and-prepare.patch')
| -rw-r--r-- | SOURCES/ALSA:-usb-audio:-Split-endpoint-setups-for-hw_params-and-prepare.patch | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/SOURCES/ALSA:-usb-audio:-Split-endpoint-setups-for-hw_params-and-prepare.patch b/SOURCES/ALSA:-usb-audio:-Split-endpoint-setups-for-hw_params-and-prepare.patch new file mode 100644 index 0000000..d23deb0 --- /dev/null +++ b/SOURCES/ALSA:-usb-audio:-Split-endpoint-setups-for-hw_params-and-prepare.patch @@ -0,0 +1,200 @@ +From 271f862ebc60b3a7ff1563654eb33cd4571c66aa Mon Sep 17 00:00:00 2001 +From: Takashi Iwai <tiwai@suse.de> +Date: Thu, 1 Sep 2022 14:41:36 +0200 +Subject: ALSA: usb-audio: Split endpoint setups for hw_params and prepare + +commit ff878b408a03bef5d610b7e2302702e16a53636e upstream. + +One of the former changes for the endpoint management was the more +consistent setup of endpoints at hw_params. +snd_usb_endpoint_configure() is a single function that does the full +setup, and it's called from both PCM hw_params and prepare callbacks. +Although the EP setup at the prepare phase is usually skipped (by +checking need_setup flag), it may be still effective in some cases +like suspend/resume that requires the interface setup again. + +As it's a full and single setup, the invocation of +snd_usb_endpoint_configure() includes not only the USB interface setup +but also the buffer release and allocation. OTOH, doing the buffer +release and re-allocation at PCM prepare phase is rather superfluous, +and better to be done only in the hw_params phase. + +For those optimizations, this patch splits the endpoint setup to two +phases: snd_usb_endpoint_set_params() and snd_usb_endpoint_prepare(), +to be called from hw_params and from prepare, respectively. + +Note that this patch changes the driver operation slightly, +effectively moving the USB interface setup again to PCM prepare stage +instead of hw_params stage, while the buffer allocation and such +initializations are still done at hw_params stage. + +And, the change of the USB interface setup timing (moving to prepare) +gave an interesting "fix", too: it was reported that the recent +kernels caused silent output at the beginning on playbacks on some +devices on Android, and this change casually fixed the regression. +It seems that those devices are picky about the sample rate change (or +the interface change?), and don't follow the too immediate rate +changes. + +Meanwhile, Android operates the PCM in the following order: +- open, then hw_params with the possibly highest sample rate +- close without prepare +- re-open, hw_params with the normal sample rate +- prepare, and start streaming +This procedure ended up the hw_params twice with different rates, and +because the recent kernel did set up the sample rate twice one and +after, it screwed up the device. OTOH, the earlier kernels didn't set +up the USB interface at hw_params, hence this problem didn't appear. + +Now, with this patch, the USB interface setup is again back to the +prepare phase, and it works around the problem automagically. +Although we should address the sample rate problem in a more solid +way in future, let's keep things working as before for now. + +Fixes: bf6313a0ff76 ("ALSA: usb-audio: Refactor endpoint management") +Cc: <stable@vger.kernel.org> +Reported-by: chihhao chen <chihhao.chen@mediatek.com> +Link: https://lore.kernel.org/r/87e6d6ae69d68dc588ac9acc8c0f24d6188375c3.camel@mediatek.com +Link: https://lore.kernel.org/r/20220901124136.4984-1-tiwai@suse.de +Signed-off-by: Takashi Iwai <tiwai@suse.de> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + sound/usb/endpoint.c | 23 +++++++++-------------- + sound/usb/endpoint.h | 6 ++++-- + sound/usb/pcm.c | 14 ++++++++++---- + 3 files changed, 23 insertions(+), 20 deletions(-) + +diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c +index f9c921683948d..ff9c7bbbc43fe 100644 +--- a/sound/usb/endpoint.c ++++ b/sound/usb/endpoint.c +@@ -758,7 +758,8 @@ bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip, + * The endpoint needs to be closed via snd_usb_endpoint_close() later. + * + * Note that this function doesn't configure the endpoint. The substream +- * needs to set it up later via snd_usb_endpoint_configure(). ++ * needs to set it up later via snd_usb_endpoint_set_params() and ++ * snd_usb_endpoint_prepare(). + */ + struct snd_usb_endpoint * + snd_usb_endpoint_open(struct snd_usb_audio *chip, +@@ -1290,12 +1291,13 @@ out_of_memory: + /* + * snd_usb_endpoint_set_params: configure an snd_usb_endpoint + * ++ * It's called either from hw_params callback. + * Determine the number of URBs to be used on this endpoint. + * An endpoint must be configured before it can be started. + * An endpoint that is already running can not be reconfigured. + */ +-static int snd_usb_endpoint_set_params(struct snd_usb_audio *chip, +- struct snd_usb_endpoint *ep) ++int snd_usb_endpoint_set_params(struct snd_usb_audio *chip, ++ struct snd_usb_endpoint *ep) + { + const struct audioformat *fmt = ep->cur_audiofmt; + int err; +@@ -1378,18 +1380,18 @@ static int init_sample_rate(struct snd_usb_audio *chip, + } + + /* +- * snd_usb_endpoint_configure: Configure the endpoint ++ * snd_usb_endpoint_prepare: Prepare the endpoint + * + * This function sets up the EP to be fully usable state. +- * It's called either from hw_params or prepare callback. ++ * It's called either from prepare callback. + * The function checks need_setup flag, and performs nothing unless needed, + * so it's safe to call this multiple times. + * + * This returns zero if unchanged, 1 if the configuration has changed, + * or a negative error code. + */ +-int snd_usb_endpoint_configure(struct snd_usb_audio *chip, +- struct snd_usb_endpoint *ep) ++int snd_usb_endpoint_prepare(struct snd_usb_audio *chip, ++ struct snd_usb_endpoint *ep) + { + bool iface_first; + int err = 0; +@@ -1410,9 +1412,6 @@ int snd_usb_endpoint_configure(struct snd_usb_audio *chip, + if (err < 0) + goto unlock; + } +- err = snd_usb_endpoint_set_params(chip, ep); +- if (err < 0) +- goto unlock; + goto done; + } + +@@ -1440,10 +1439,6 @@ int snd_usb_endpoint_configure(struct snd_usb_audio *chip, + if (err < 0) + goto unlock; + +- err = snd_usb_endpoint_set_params(chip, ep); +- if (err < 0) +- goto unlock; +- + err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt); + if (err < 0) + goto unlock; +diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h +index 6a9af04cf175a..e67ea28faa54f 100644 +--- a/sound/usb/endpoint.h ++++ b/sound/usb/endpoint.h +@@ -17,8 +17,10 @@ snd_usb_endpoint_open(struct snd_usb_audio *chip, + bool is_sync_ep); + void snd_usb_endpoint_close(struct snd_usb_audio *chip, + struct snd_usb_endpoint *ep); +-int snd_usb_endpoint_configure(struct snd_usb_audio *chip, +- struct snd_usb_endpoint *ep); ++int snd_usb_endpoint_set_params(struct snd_usb_audio *chip, ++ struct snd_usb_endpoint *ep); ++int snd_usb_endpoint_prepare(struct snd_usb_audio *chip, ++ struct snd_usb_endpoint *ep); + int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock); + + bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip, +diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c +index e692ae04436a5..02035b545f9dd 100644 +--- a/sound/usb/pcm.c ++++ b/sound/usb/pcm.c +@@ -443,17 +443,17 @@ static int configure_endpoints(struct snd_usb_audio *chip, + if (stop_endpoints(subs, false)) + sync_pending_stops(subs); + if (subs->sync_endpoint) { +- err = snd_usb_endpoint_configure(chip, subs->sync_endpoint); ++ err = snd_usb_endpoint_prepare(chip, subs->sync_endpoint); + if (err < 0) + return err; + } +- err = snd_usb_endpoint_configure(chip, subs->data_endpoint); ++ err = snd_usb_endpoint_prepare(chip, subs->data_endpoint); + if (err < 0) + return err; + snd_usb_set_format_quirk(subs, subs->cur_audiofmt); + } else { + if (subs->sync_endpoint) { +- err = snd_usb_endpoint_configure(chip, subs->sync_endpoint); ++ err = snd_usb_endpoint_prepare(chip, subs->sync_endpoint); + if (err < 0) + return err; + } +@@ -551,7 +551,13 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream, + subs->cur_audiofmt = fmt; + mutex_unlock(&chip->mutex); + +- ret = configure_endpoints(chip, subs); ++ if (subs->sync_endpoint) { ++ ret = snd_usb_endpoint_set_params(chip, subs->sync_endpoint); ++ if (ret < 0) ++ goto unlock; ++ } ++ ++ ret = snd_usb_endpoint_set_params(chip, subs->data_endpoint); + + unlock: + if (ret < 0) +-- +cgit + |