ALSA: snd-usb: fix some typos in endpoint.c documentation
Also be more specific about some details while at it. Signed-off-by: Daniel Mack <zonque@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>hifive-unleashed-5.1
Daniel Mack
Takashi Iwai
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e9f66d9b9c
commit
07a5e9d4fd
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@ -40,25 +40,26 @@
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* USB endpoint and its streaming.
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*
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* There are functions to activate and deactivate the streaming URBs and
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* optinal callbacks to let the pcm logic handle the actual content of the
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* optional callbacks to let the pcm logic handle the actual content of the
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* packets for playback and record. Thus, the bus streaming and the audio
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* handlers are fully decoupled.
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*
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* There are two different types of endpoints in for audio applications.
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* There are two different types of endpoints in audio applications.
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*
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* SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
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* inbound and outbound traffic.
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*
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* SND_USB_ENDPOINT_TYPE_SYNC are for inbound traffic only and expect the
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* payload to carry Q16.16 formatted sync information (3 or 4 bytes).
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* SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
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* expect the payload to carry Q10.14 / Q16.16 formatted sync information
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* (3 or 4 bytes).
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*
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* Each endpoint has to be configured (by calling
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* snd_usb_endpoint_set_params()) before it can be used.
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* Each endpoint has to be configured prior to being used by calling
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* snd_usb_endpoint_set_params().
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*
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* The model incorporates a reference counting, so that multiple users
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* can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
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* only the first user will effectively start the URBs, and only the last
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* one will tear them down again.
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* one to stop it will tear the URBs down again.
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*/
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/*
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@ -120,7 +121,7 @@ static const char *usb_error_string(int err)
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/**
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* snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
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*
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* @ep: The endpoint
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* @ep: The snd_usb_endpoint
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*
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* Determine whether an endpoint is driven by an implicit feedback
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* data endpoint source.
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@ -278,17 +279,18 @@ static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
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}
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/*
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* Send output urbs that have been prepared previously. Urbs are dequeued
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* Send output urbs that have been prepared previously. URBs are dequeued
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* from ep->ready_playback_urbs and in case there there aren't any available
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* or there are no packets that have been prepared, this function does
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* nothing.
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*
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* The reason why the functionality of sending and preparing urbs is separated
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* is that host controllers don't guarantee an ordering in returing inbound
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* and outbound packets to their submitters.
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* The reason why the functionality of sending and preparing URBs is separated
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* is that host controllers don't guarantee the order in which they return
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* inbound and outbound packets to their submitters.
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*
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* This function is only used for implicit feedback endpoints. For endpoints
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* driven by sync endpoints, urbs are submitted from their completion handler.
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* driven by dedicated sync endpoints, URBs are immediately re-submitted
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* from their completion handler.
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*/
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static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
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{
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@ -391,7 +393,7 @@ exit_clear:
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}
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/**
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* snd_usb_add_endpoint: Add an endpoint to an audio chip
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* snd_usb_add_endpoint: Add an endpoint to an USB audio chip
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*
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* @chip: The chip
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* @alts: The USB host interface
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@ -745,11 +747,14 @@ out_of_memory:
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}
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/**
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* snd_usb_endpoint_set_params: configure an snd_endpoint
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* snd_usb_endpoint_set_params: configure an snd_usb_endpoint
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*
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* @ep: the endpoint to configure
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* @ep: the snd_usb_endpoint to configure
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* @hw_params: the hardware parameters
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* @fmt: the USB audio format information
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* @sync_ep: the sync endpoint to use, if any
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*
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* Determine the number of of URBs to be used on this endpoint.
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* Determine the number of URBs to be used on this endpoint.
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* An endpoint must be configured before it can be started.
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* An endpoint that is already running can not be reconfigured.
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*/
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@ -807,7 +812,7 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
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* @ep: the endpoint to start
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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 this not already running, the URBs for this endpoint will be
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* In case it is not already running, the URBs for this endpoint will be
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* submitted. Otherwise, this function does nothing.
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*
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* Must be balanced to calls of snd_usb_endpoint_stop().
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@ -840,7 +845,8 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
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/*
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* If this endpoint has a data endpoint as implicit feedback source,
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* don't start the urbs here. Instead, mark them all as available,
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* wait for the record urbs to arrive and queue from that context.
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* wait for the record urbs to return and queue the playback urbs
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* from that context.
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*/
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set_bit(EP_FLAG_RUNNING, &ep->flags);
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@ -892,7 +898,7 @@ __error:
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*
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* A call to this function will decrement the use count of the endpoint.
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* In case the last user has requested the endpoint stop, the URBs will
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* actually deactivated.
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* actually be deactivated.
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*
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* Must be balanced to calls of snd_usb_endpoint_start().
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*/
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@ -994,7 +1000,8 @@ int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
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return -EBUSY;
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}
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/** snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
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/**
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* snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
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*
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* @ep: the list header of the endpoint to free
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*
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@ -1032,8 +1039,9 @@ void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
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/*
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* In case the endpoint is operating in implicit feedback mode, prepare
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* and a new outbound URB that has the same layout as the received
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* packet and add it to the list of pending urbs.
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* a new outbound URB that has the same layout as the received packet
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* and add it to the list of pending urbs. queue_pending_output_urbs()
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* will take care of them later.
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*/
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if (snd_usb_endpoint_implict_feedback_sink(ep) &&
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ep->use_count != 0) {
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@ -1063,8 +1071,8 @@ void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
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/*
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* Iterate through the inbound packet and prepare the lengths
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* for the output packet. The OUT packet we are about to send
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* will have the same amount of payload than the IN packet we
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* just received.
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* will have the same amount of payload bytes than the IN
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* packet we just received.
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*/
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out_packet->packets = in_ctx->packets;
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