[alsa-devel] [PATCH] ALSA: snd-usb-usx2y: remove bogus frame check

[Takashi Iwai]

At Wed,  2 Oct 2013 15:54:28 +0200,
Daniel Mack wrote:
> 
> The frame check in i_usX2Y_urb_complete() is bogus and produces false
> positives as described in this LAU thread:
> 
>   http://linuxaudio.org/mailarchive/lau/2013/5/20/200177
> 
> This code removes the check code entirely.
> 
> Cc: fzu at wemgehoertderstaat.de
> Reported-by: Dr Nicholas J Bailey <nicholas.bailey at glasgow.ac.uk>
> Suggested-by: Takashi Iwai <tiwai at suse.de>
> Signed-off-by: Daniel Mack <zonque at gmail.com>

It's referred in usx2yhwdeppcm.c, too (the file is included there).

Yeah, I know that the driver code is fairly complex (IOW ugly).  IIRC,
the hwdeppcm mmap is also broken, and we need yet another fix.
Sigh...


thanks,

Takashi

> ---
>  sound/usb/usx2y/usbusx2yaudio.c | 22 +++-------------------
>  1 file changed, 3 insertions(+), 19 deletions(-)
> 
> diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c
> index 63fb521..6234a51 100644
> --- a/sound/usb/usx2y/usbusx2yaudio.c
> +++ b/sound/usb/usx2y/usbusx2yaudio.c
> @@ -299,19 +299,6 @@ static void usX2Y_error_urb_status(struct usX2Ydev *usX2Y,
>  	usX2Y_clients_stop(usX2Y);
>  }
>  
> -static void usX2Y_error_sequence(struct usX2Ydev *usX2Y,
> -				 struct snd_usX2Y_substream *subs, struct urb *urb)
> -{
> -	snd_printk(KERN_ERR
> -"Sequence Error!(hcd_frame=%i ep=%i%s;wait=%i,frame=%i).\n"
> -"Most probably some urb of usb-frame %i is still missing.\n"
> -"Cause could be too long delays in usb-hcd interrupt handling.\n",
> -		   usb_get_current_frame_number(usX2Y->dev),
> -		   subs->endpoint, usb_pipein(urb->pipe) ? "in" : "out",
> -		   usX2Y->wait_iso_frame, urb->start_frame, usX2Y->wait_iso_frame);
> -	usX2Y_clients_stop(usX2Y);
> -}
> -
>  static void i_usX2Y_urb_complete(struct urb *urb)
>  {
>  	struct snd_usX2Y_substream *subs = urb->context;
> @@ -328,12 +315,9 @@ static void i_usX2Y_urb_complete(struct urb *urb)
>  		usX2Y_error_urb_status(usX2Y, subs, urb);
>  		return;
>  	}
> -	if (likely((urb->start_frame & 0xFFFF) == (usX2Y->wait_iso_frame & 0xFFFF)))
> -		subs->completed_urb = urb;
> -	else {
> -		usX2Y_error_sequence(usX2Y, subs, urb);
> -		return;
> -	}
> +
> +	subs->completed_urb = urb;
> +
>  	{
>  		struct snd_usX2Y_substream *capsubs = usX2Y->subs[SNDRV_PCM_STREAM_CAPTURE],
>  			*playbacksubs = usX2Y->subs[SNDRV_PCM_STREAM_PLAYBACK];
> -- 
> 1.8.3.1
>