132 lines
4.6 KiB
Diff
132 lines
4.6 KiB
Diff
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From 42ff3e2d34427dc4c6faa09052a2531f2e71d7d6 Mon Sep 17 00:00:00 2001
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From: Daniel Mack <zonque@gmail.com>
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Date: Wed, 29 Aug 2012 13:17:05 +0200
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Subject: [PATCH] ALSA: snd-usb: Fix URB cancellation at stream start
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Commit e9ba389c5 ("ALSA: usb-audio: Fix scheduling-while-atomic bug in
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PCM capture stream") fixed a scheduling-while-atomic bug that happened
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when snd_usb_endpoint_start was called from the trigger callback, which
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is an atmic context. However, the patch breaks the idea of the endpoints
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reference counting, which is the reason why the driver has been
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refactored lately.
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Revert that commit and let snd_usb_endpoint_start() take care of the URB
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cancellation again. As this function is called from both atomic and
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non-atomic context, add a flag to denote whether the function may sleep.
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Signed-off-by: Daniel Mack <zonque@gmail.com>
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Cc: stable@kernel.org [3.5+]
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---
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sound/usb/endpoint.c | 11 +++++++++--
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sound/usb/endpoint.h | 2 +-
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sound/usb/pcm.c | 13 +++++--------
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3 files changed, 15 insertions(+), 11 deletions(-)
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diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
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index c411812..b896c55 100644
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--- a/sound/usb/endpoint.c
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+++ b/sound/usb/endpoint.c
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@@ -799,7 +799,9 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
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/**
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* snd_usb_endpoint_start: start an snd_usb_endpoint
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*
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- * @ep: the endpoint to start
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+ * @ep: the endpoint to start
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+ * @can_sleep: flag indicating whether the operation is executed in
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+ * non-atomic context
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*
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* A call to this function will increment the use count of the endpoint.
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* In case it is not already running, the URBs for this endpoint will be
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@@ -809,7 +811,7 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
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*
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* Returns an error if the URB submission failed, 0 in all other cases.
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*/
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-int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
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+int snd_usb_endpoint_start(struct snd_usb_endpoint *ep, int can_sleep)
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{
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int err;
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unsigned int i;
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@@ -821,6 +823,11 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
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if (++ep->use_count != 1)
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return 0;
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+ /* just to be sure */
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+ deactivate_urbs(ep, 0, can_sleep);
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+ if (can_sleep)
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+ wait_clear_urbs(ep);
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+
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ep->active_mask = 0;
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ep->unlink_mask = 0;
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ep->phase = 0;
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diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
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index ee2723f..a8e60c1 100644
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--- a/sound/usb/endpoint.h
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+++ b/sound/usb/endpoint.h
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@@ -13,7 +13,7 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
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struct audioformat *fmt,
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struct snd_usb_endpoint *sync_ep);
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-int snd_usb_endpoint_start(struct snd_usb_endpoint *ep);
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+int snd_usb_endpoint_start(struct snd_usb_endpoint *ep, int can_sleep);
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void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep,
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int force, int can_sleep, int wait);
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int snd_usb_endpoint_activate(struct snd_usb_endpoint *ep);
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diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
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index 62ec808..1546577 100644
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--- a/sound/usb/pcm.c
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+++ b/sound/usb/pcm.c
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@@ -212,7 +212,7 @@ int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
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}
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}
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-static int start_endpoints(struct snd_usb_substream *subs)
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+static int start_endpoints(struct snd_usb_substream *subs, int can_sleep)
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{
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int err;
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@@ -225,7 +225,7 @@ static int start_endpoints(struct snd_usb_substream *subs)
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snd_printdd(KERN_DEBUG "Starting data EP @%p\n", ep);
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ep->data_subs = subs;
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- err = snd_usb_endpoint_start(ep);
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+ err = snd_usb_endpoint_start(ep, can_sleep);
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if (err < 0) {
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clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
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return err;
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@@ -239,7 +239,7 @@ static int start_endpoints(struct snd_usb_substream *subs)
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snd_printdd(KERN_DEBUG "Starting sync EP @%p\n", ep);
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ep->sync_slave = subs->data_endpoint;
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- err = snd_usb_endpoint_start(ep);
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+ err = snd_usb_endpoint_start(ep, can_sleep);
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if (err < 0) {
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clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
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return err;
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@@ -544,13 +544,10 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
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subs->last_frame_number = 0;
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runtime->delay = 0;
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- /* clear the pending deactivation on the target EPs */
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- deactivate_endpoints(subs);
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-
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/* for playback, submit the URBs now; otherwise, the first hwptr_done
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* updates for all URBs would happen at the same time when starting */
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if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
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- return start_endpoints(subs);
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+ return start_endpoints(subs, 1);
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return 0;
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}
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@@ -1175,7 +1172,7 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
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switch (cmd) {
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case SNDRV_PCM_TRIGGER_START:
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- err = start_endpoints(subs);
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+ err = start_endpoints(subs, 0);
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if (err < 0)
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return err;
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--
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1.7.11.4
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