At Tue, 24 Apr 2012 19:31:24 +0200, Daniel Mack wrote:
Also be more specific about some details while at it.
Signed-off-by: Daniel Mack zonque@gmail.com
Thanks, applied.
Takashi
sound/usb/endpoint.c | 58 ++++++++++++++++++++++++++++--------------------- 1 files changed, 33 insertions(+), 25 deletions(-)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index 12e5a95..286a8d2 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -40,25 +40,26 @@
- USB endpoint and its streaming.
- There are functions to activate and deactivate the streaming URBs and
- optinal callbacks to let the pcm logic handle the actual content of the
- optional callbacks to let the pcm logic handle the actual content of the
- packets for playback and record. Thus, the bus streaming and the audio
- handlers are fully decoupled.
- There are two different types of endpoints in for audio applications.
- There are two different types of endpoints in audio applications.
- SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
- inbound and outbound traffic.
- SND_USB_ENDPOINT_TYPE_SYNC are for inbound traffic only and expect the
- payload to carry Q16.16 formatted sync information (3 or 4 bytes).
- SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
- expect the payload to carry Q10.14 / Q16.16 formatted sync information
- (3 or 4 bytes).
- Each endpoint has to be configured (by calling
- snd_usb_endpoint_set_params()) before it can be used.
- Each endpoint has to be configured prior to being used by calling
- snd_usb_endpoint_set_params().
- The model incorporates a reference counting, so that multiple users
- can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
- only the first user will effectively start the URBs, and only the last
- one will tear them down again.
*/
- one to stop it will tear the URBs down again.
/* @@ -120,7 +121,7 @@ static const char *usb_error_string(int err) /**
- snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
- @ep: The endpoint
- @ep: The snd_usb_endpoint
- Determine whether an endpoint is driven by an implicit feedback
- data endpoint source.
@@ -278,17 +279,18 @@ static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep, }
/*
- Send output urbs that have been prepared previously. Urbs are dequeued
- Send output urbs that have been prepared previously. URBs are dequeued
- from ep->ready_playback_urbs and in case there there aren't any available
- or there are no packets that have been prepared, this function does
- nothing.
- The reason why the functionality of sending and preparing urbs is separated
- is that host controllers don't guarantee an ordering in returing inbound
- and outbound packets to their submitters.
- The reason why the functionality of sending and preparing URBs is separated
- is that host controllers don't guarantee the order in which they return
- inbound and outbound packets to their submitters.
- This function is only used for implicit feedback endpoints. For endpoints
- driven by sync endpoints, urbs are submitted from their completion handler.
- driven by dedicated sync endpoints, URBs are immediately re-submitted
*/
- from their completion handler.
static void queue_pending_output_urbs(struct snd_usb_endpoint *ep) { @@ -391,7 +393,7 @@ exit_clear: }
/**
- snd_usb_add_endpoint: Add an endpoint to an audio chip
- snd_usb_add_endpoint: Add an endpoint to an USB audio chip
- @chip: The chip
- @alts: The USB host interface
@@ -745,11 +747,14 @@ out_of_memory: }
/**
- snd_usb_endpoint_set_params: configure an snd_endpoint
- snd_usb_endpoint_set_params: configure an snd_usb_endpoint
- @ep: the endpoint to configure
- @ep: the snd_usb_endpoint to configure
- @hw_params: the hardware parameters
- @fmt: the USB audio format information
- @sync_ep: the sync endpoint to use, if any
- Determine the number of of URBs to be used on this endpoint.
*/
- 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.
@@ -807,7 +812,7 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
- @ep: the endpoint to start
- A call to this function will increment the use count of the endpoint.
- In case this not already running, the URBs for this endpoint will be
- In case it is not already running, the URBs for this endpoint will be
- submitted. Otherwise, this function does nothing.
- Must be balanced to calls of snd_usb_endpoint_stop().
@@ -840,7 +845,8 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep) /* * If this endpoint has a data endpoint as implicit feedback source, * don't start the urbs here. Instead, mark them all as available,
* wait for the record urbs to arrive and queue from that context.
* wait for the record urbs to return and queue the playback urbs* from that context.*/
set_bit(EP_FLAG_RUNNING, &ep->flags);
@@ -892,7 +898,7 @@ __error:
- A call to this function will decrement the use count of the endpoint.
- In case the last user has requested the endpoint stop, the URBs will
- actually deactivated.
*/
- actually be deactivated.
- Must be balanced to calls of snd_usb_endpoint_start().
@@ -994,7 +1000,8 @@ int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep) return -EBUSY; }
-/** snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint +/**
- snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
- @ep: the list header of the endpoint to free
@@ -1032,8 +1039,9 @@ void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
/* * In case the endpoint is operating in implicit feedback mode, prepare
* and a new outbound URB that has the same layout as the received* packet and add it to the list of pending urbs.
* a new outbound URB that has the same layout as the received packet* and add it to the list of pending urbs. queue_pending_output_urbs()* will take care of them later.@@ -1063,8 +1071,8 @@ void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, /* * Iterate through the inbound packet and prepare the lengths * for the output packet. The OUT packet we are about to send
* will have the same amount of payload than the IN packet we* just received.
* will have the same amount of payload bytes than the IN* packet we just received.*/
out_packet->packets = in_ctx->packets;
-- 1.7.5.4