245baf983c
In order to support devices with implicit feedback streaming models, packet sizes are now stored with each individual urb, and the PCM handling code which fills the buffers purely relies on the size fields now. However, calling snd_usb_audio_next_packet_size() for all possible packets in an URB at once, prior to letting the PCM code do its job does in fact not lead to the same behaviour than what the old code did: The PCM code will break its loop once a period boundary is reached, consequently using up less packets that it really could. As snd_usb_audio_next_packet_size() implements a feedback mechanism to the endpoints phase accumulator, the number of calls to that function matters, and when called too often, the data rate runs out of bounds. Fix this by making the next_packet function public, and call it from the PCM code as before if the packet data sizes are not defined. Signed-off-by: Daniel Mack <zonque@gmail.com> Cc: stable@kernel.org [v3.5+] Signed-off-by: Takashi Iwai <tiwai@suse.de>
31 lines
1.1 KiB
C
31 lines
1.1 KiB
C
#ifndef __USBAUDIO_ENDPOINT_H
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#define __USBAUDIO_ENDPOINT_H
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#define SND_USB_ENDPOINT_TYPE_DATA 0
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#define SND_USB_ENDPOINT_TYPE_SYNC 1
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struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
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struct usb_host_interface *alts,
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int ep_num, int direction, int type);
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int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
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struct snd_pcm_hw_params *hw_params,
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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, 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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int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep);
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void snd_usb_endpoint_free(struct list_head *head);
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int snd_usb_endpoint_implict_feedback_sink(struct snd_usb_endpoint *ep);
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int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep);
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void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
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struct snd_usb_endpoint *sender,
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const struct urb *urb);
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#endif /* __USBAUDIO_ENDPOINT_H */
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