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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: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2016-01-11 14:39:12 +01:00
parent 79289e2419
commit e270336331
1 changed files with 47 additions and 0 deletions
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47
sound/usb/card.c
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@ -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;