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Commit 342cda29343a6272c630f94ed56810a76740251b

Authored by Clemens Ladisch
Committed by Takashi Iwai
1 parent d81bf8cf54
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

ALSA: usb-audio: work around Android accessory firmware bug 

When the Android firmware enables the audio interfaces in accessory
mode, it always declares in the control interface's baInterfaceNr array
that interfaces 0 and 1 belong to the audio function.  However, the
accessory interface itself, if also enabled, already is at index 0 and
shifts the actual audio interface numbers to 1 and 2, which prevents the
PCM streaming interface from being seen by the host driver.

To get the PCM interface interface to work, detect when the descriptors
point to the (for this driver useless) accessory interface, and redirect
to the correct one.

Reported-by: Jeremy Rosen <jeremy.rosen@openwide.fr>
Tested-by: Jeremy Rosen <jeremy.rosen@openwide.fr>
Cc: <stable@vger.kernel.org>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Showing 1 changed file with 20 additions and 2 deletions Side-by-side Diff

... ... @@ -147,14 +147,32 @@
147 147 return -EINVAL;
148 148 }
149 149  
  150 + alts = &iface->altsetting[0];
  151 + altsd = get_iface_desc(alts);
  152 +
  153 + /*
  154 + * Android with both accessory and audio interfaces enabled gets the
  155 + * interface numbers wrong.
  156 + */
  157 + if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
  158 + chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
  159 + interface == 0 &&
  160 + altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
  161 + altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
  162 + interface = 2;
  163 + iface = usb_ifnum_to_if(dev, interface);
  164 + if (!iface)
  165 + return -EINVAL;
  166 + alts = &iface->altsetting[0];
  167 + altsd = get_iface_desc(alts);
  168 + }
  169 +
150 170 if (usb_interface_claimed(iface)) {
151 171 snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
152 172 dev->devnum, ctrlif, interface);
153 173 return -EINVAL;
154 174 }
155 175  
156   - alts = &iface->altsetting[0];
157   - altsd = get_iface_desc(alts);
158 176 if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
159 177 altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
160 178 altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {