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Commit e2703363 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: Add quirk_alias option 



This patch adds a new option "quirk_alias" to snd-usb-audio driver for
allowing user to pass the quirk alias list.  A quirk alias consists of
a string form like 0123abcd:5678beef, which makes to apply a quirk to
a device with USB ID 0123:abcd treated as if it were 5678:beef.
This feature is useful to test an existing quirk, typically for a
newer model of the same vendor, without patching / rebuilding the
kernel driver.

The current implementation is fairly simplistic: since there is no API
for matching a usb_device_id to the given ID pair, it has an open code
to loop over the id table and matches only with vendor:product pair.
So far, this is OK, as all existing entries are with vendor:product
pairs, indeed.  Once when we have another matching entry, however,
we'd need to update get_alias_quirk() as well.

Note that this option is provided only for testing / development.  If
you want to have a proper support, contact to upstream for adding the
matching quirk in the driver code statically.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 79289e24

sound/usb/card.c

+47 −0
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 }; 
static int device_setup[SNDRV_CARDS]; /* device parameter for this card */

static bool ignore_ctl_error;

static bool autoclock = true;

static char *quirk_alias[SNDRV_CARDS];



module_param_array(index, int, NULL, 0444);

MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
@@ -100,6 +101,8 @@ MODULE_PARM_DESC(ignore_ctl_error, 
		 "Ignore errors from USB controller for mixer interfaces.");

module_param(autoclock, bool, 0444);

MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");

module_param_array(quirk_alias, charp, NULL, 0444);

MODULE_PARM_DESC(quirk_alias, "Quirk aliases, e.g. 0123abcd:5678beef.");



/*

 * we keep the snd_usb_audio_t instances by ourselves for merging
@@ -457,6 +460,48 @@ static int snd_usb_audio_create(struct usb_interface *intf, 
	return 0;

}



/* look for a matching quirk alias id */

static bool get_alias_id(struct usb_device *dev, unsigned int *id)

{

	int i;

	unsigned int src, dst;



	for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {

		if (!quirk_alias[i] ||

		    sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||

		    src != *id)

			continue;

		dev_info(&dev->dev,

			 "device (%04x:%04x): applying quirk alias %04x:%04x\n",

			 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),

			 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));

		*id = dst;

		return true;

	}



	return false;

}



static struct usb_device_id usb_audio_ids[]; /* defined below */



/* look for the corresponding quirk */

static const struct snd_usb_audio_quirk *

get_alias_quirk(struct usb_device *dev, unsigned int id)

{

	const struct usb_device_id *p;



	for (p = usb_audio_ids; p->match_flags; p++) {

		/* FIXME: this checks only vendor:product pair in the list */

		if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) ==

		    USB_DEVICE_ID_MATCH_DEVICE &&

		    p->idVendor == USB_ID_VENDOR(id) &&

		    p->idProduct == USB_ID_PRODUCT(id))

			return (const struct snd_usb_audio_quirk *)p->driver_info;

	}



	return NULL;

}



/*

 * probe the active usb device

 *
@@ -483,6 +528,8 @@ static int usb_audio_probe(struct usb_interface *intf, 
	ifnum = get_iface_desc(alts)->bInterfaceNumber;

	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),

		    le16_to_cpu(dev->descriptor.idProduct));

	if (get_alias_id(dev, &id))

		quirk = get_alias_quirk(dev, id);

	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)

		return -ENXIO;