[alsa-devel] [PATCH] ALSA: line6: Always setup isochronous transfer properties

[Takashi Iwai]

On Mon, 06 Feb 2017 20:34:58 +0100,
Andrej Krutak wrote:
> 
> While not all line6 devices currently support PCM, it causes no
> harm to 'have it prepared'.
> 
> This also fixes toneport, which only has PCM - in which case
> we previously skipped the USB transfer properties detection completely.
> 
> Signed-off-by: Andrej Krutak <dev at andree.sk>

Well, this looks too complex and vague as a regression fix.  If it
were 4.10-rc1, I could take it.  But now it's already rc7 and the next
might be final, so I prefer a shorter and easier solution.

That said, we can revert the commit as a clear fix at first for 4.10
(with Cc to stable), then take this on top as an enhancement for
4.11.

Still it's important to know whether this works on Igor's system, so
Igor, please give this one try.


thanks,

Takashi

> ---
>  sound/usb/line6/driver.c | 49 ++++++++++++++++++++++++++----------------------
>  1 file changed, 27 insertions(+), 22 deletions(-)
> 
> diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
> index 90009c0..0ff5a7d 100644
> --- a/sound/usb/line6/driver.c
> +++ b/sound/usb/line6/driver.c
> @@ -492,42 +492,46 @@ static void line6_destruct(struct snd_card *card)
>  	usb_put_dev(usbdev);
>  }
>  
> -/* get data from endpoint descriptor (see usb_maxpacket): */
> -static void line6_get_interval(struct usb_line6 *line6)
> +static void line6_get_usb_properties(struct usb_line6 *line6)
>  {
>  	struct usb_device *usbdev = line6->usbdev;
>  	const struct line6_properties *properties = line6->properties;
>  	int pipe;
> -	struct usb_host_endpoint *ep;
> +	struct usb_host_endpoint *ep = NULL;
>  
> -	if (properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
> -		pipe =
> -			usb_rcvintpipe(line6->usbdev, line6->properties->ep_ctrl_r);
> -	} else {
> -		pipe =
> -			usb_rcvbulkpipe(line6->usbdev, line6->properties->ep_ctrl_r);
> +	if (properties->capabilities & LINE6_CAP_CONTROL) {
> +		if (properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
> +			pipe = usb_rcvintpipe(line6->usbdev,
> +				line6->properties->ep_ctrl_r);
> +		} else {
> +			pipe = usb_rcvbulkpipe(line6->usbdev,
> +				line6->properties->ep_ctrl_r);
> +		}
> +		ep = usbdev->ep_in[usb_pipeendpoint(pipe)];
>  	}
> -	ep = usbdev->ep_in[usb_pipeendpoint(pipe)];
>  
> +	/* Control data transfer properties */
>  	if (ep) {
>  		line6->interval = ep->desc.bInterval;
> -		if (usbdev->speed == USB_SPEED_LOW) {
> -			line6->intervals_per_second = USB_LOW_INTERVALS_PER_SECOND;
> -			line6->iso_buffers = USB_LOW_ISO_BUFFERS;
> -		} else {
> -			line6->intervals_per_second = USB_HIGH_INTERVALS_PER_SECOND;
> -			line6->iso_buffers = USB_HIGH_ISO_BUFFERS;
> -		}
> -
>  		line6->max_packet_size = le16_to_cpu(ep->desc.wMaxPacketSize);
>  	} else {
> -		dev_err(line6->ifcdev,
> -			"endpoint not available, using fallback values");
> +		if (properties->capabilities & LINE6_CAP_CONTROL) {
> +			dev_err(line6->ifcdev,
> +				"endpoint not available, using fallback values");
> +		}
>  		line6->interval = LINE6_FALLBACK_INTERVAL;
>  		line6->max_packet_size = LINE6_FALLBACK_MAXPACKETSIZE;
>  	}
> -}
>  
> +	/* Isochronous transfer properties */
> +	if (usbdev->speed == USB_SPEED_LOW) {
> +		line6->intervals_per_second = USB_LOW_INTERVALS_PER_SECOND;
> +		line6->iso_buffers = USB_LOW_ISO_BUFFERS;
> +	} else {
> +		line6->intervals_per_second = USB_HIGH_INTERVALS_PER_SECOND;
> +		line6->iso_buffers = USB_HIGH_ISO_BUFFERS;
> +	}
> +}
>  
>  /* Enable buffering of incoming messages, flush the buffer */
>  static int line6_hwdep_open(struct snd_hwdep *hw, struct file *file)
> @@ -754,8 +758,9 @@ int line6_probe(struct usb_interface *interface,
>  		goto error;
>  	}
>  
> +	line6_get_usb_properties(line6);
> +
>  	if (properties->capabilities & LINE6_CAP_CONTROL) {
> -		line6_get_interval(line6);
>  		ret = line6_init_cap_control(line6);
>  		if (ret < 0)
>  			goto error;
> -- 
> 2.7.4
>