[alsa-devel] [PATCH] ALSA: line6: Claim POD X3 USB data interface

[Takashi Iwai]

On Sat, 19 Nov 2016 13:01:29 +0100,
Andrej Krutak wrote:
> 
> Deny userspace from using the interface concurrently.

Could you clarify more what's wrong and what you're changing?


thanks,

Takashi

> 
> Signed-off-by: Andrej Krutak <dev at andree.sk>
> ---
>  sound/usb/line6/driver.h |  1 +
>  sound/usb/line6/podhd.c  | 24 ++++++++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/sound/usb/line6/driver.h b/sound/usb/line6/driver.h
> index 7e3a3aa..5d18957 100644
> --- a/sound/usb/line6/driver.h
> +++ b/sound/usb/line6/driver.h
> @@ -98,6 +98,7 @@ struct line6_properties {
>  
>  	int altsetting;
>  
> +	unsigned ctrl_if;
>  	unsigned ep_ctrl_r;
>  	unsigned ep_ctrl_w;
>  	unsigned ep_audio_r;
> diff --git a/sound/usb/line6/podhd.c b/sound/usb/line6/podhd.c
> index 49cd4a6..6c53b87 100644
> --- a/sound/usb/line6/podhd.c
> +++ b/sound/usb/line6/podhd.c
> @@ -153,6 +153,7 @@ struct usb_line6_podhd {
>  			    .rats = &podhd_ratden},
>  	.bytes_per_channel = 3 /* SNDRV_PCM_FMTBIT_S24_3LE */
>  };
> +static struct usb_driver podhd_driver;
>  
>  static void podhd_startup_start_workqueue(unsigned long data);
>  static void podhd_startup_workqueue(struct work_struct *work);
> @@ -291,8 +292,13 @@ static void podhd_disconnect(struct usb_line6 *line6)
>  	struct usb_line6_podhd *pod = (struct usb_line6_podhd *)line6;
>  
>  	if (pod->line6.properties->capabilities & LINE6_CAP_CONTROL) {
> +		struct usb_interface *intf;
> +
>  		del_timer_sync(&pod->startup_timer);
>  		cancel_work_sync(&pod->startup_work);
> +
> +		intf = usb_ifnum_to_if(line6->usbdev, pod->line6.properties->ctrl_if);
> +		usb_driver_release_interface(&podhd_driver, intf);
>  	}
>  }
>  
> @@ -304,10 +310,26 @@ static int podhd_init(struct usb_line6 *line6,
>  {
>  	int err;
>  	struct usb_line6_podhd *pod = (struct usb_line6_podhd *) line6;
> +	struct usb_interface *intf;
>  
>  	line6->disconnect = podhd_disconnect;
>  
>  	if (pod->line6.properties->capabilities & LINE6_CAP_CONTROL) {
> +		/* claim the data interface */
> +		intf = usb_ifnum_to_if(line6->usbdev, pod->line6.properties->ctrl_if);
> +		if (!intf) {
> +			dev_err(pod->line6.ifcdev, "interface %d not found\n",
> +			        pod->line6.properties->ctrl_if);
> +			return -ENODEV;
> +		}
> +
> +		err = usb_driver_claim_interface(&podhd_driver, intf, NULL);
> +		if (err != 0) {
> +			dev_err(pod->line6.ifcdev, "can't claim interface %d, error %d\n",
> +			        pod->line6.properties->ctrl_if, err);
> +			return err;
> +		}
> +
>  		/* create sysfs entries: */
>  		err = snd_card_add_dev_attr(line6->card, &podhd_dev_attr_group);
>  		if (err < 0)
> @@ -406,6 +428,7 @@ static int podhd_init(struct usb_line6 *line6,
>  		.altsetting = 1,
>  		.ep_ctrl_r = 0x81,
>  		.ep_ctrl_w = 0x01,
> +		.ctrl_if = 1,
>  		.ep_audio_r = 0x86,
>  		.ep_audio_w = 0x02,
>  	},
> @@ -417,6 +440,7 @@ static int podhd_init(struct usb_line6 *line6,
>  		.altsetting = 1,
>  		.ep_ctrl_r = 0x81,
>  		.ep_ctrl_w = 0x01,
> +		.ctrl_if = 1,
>  		.ep_audio_r = 0x86,
>  		.ep_audio_w = 0x02,
>  	},
> -- 
> 1.9.1
> 
>