Paul Bonser wrote:
> On 01/08/2015 03:56 PM, Clemens Ladisch wrote:
>> Paul Bonser wrote:
>>> The Akai MPC Element incorrectly reports its bInterfaceClass as 255, but
>>> otherwise implements the USB MIDI spec correctly.
>>>
>>> This adds a quirks-table.h entry which allows the device to be
>>> recognized as a standard USB MIDI device.
>>>
>>> +++ b/sound/usb/quirks-table.h
>>> +{
>>> + /* Akai MPC Element */
>>> + USB_DEVICE(0x09e8, 0x0021),
>>> + .driver_info = (unsigned long) & (const struct snd_usb_audio_quirk) {
>>> + .ifnum = QUIRK_ANY_INTERFACE,
>>> + .type = QUIRK_COMPOSITE,
>>> + .data = & (const struct snd_usb_audio_quirk[]) {
>>> + {
>>> + .ifnum = 0,
>>> + .type = QUIRK_IGNORE_INTERFACE
>>> + },
>>> + {
>>> + .ifnum = 1,
>>> + .type = QUIRK_MIDI_STANDARD_INTERFACE
>>> + },
>>> + {
>>> + .ifnum = -1
>>> + }
>>> + }
>>> + }
>>> +},
>>
>> Why a composite quirk? Does a single quirk entry not work?
>
> A single quirk entry results in an error message in dmesg:
> "snd-usb-audio: probe of 3-2:1.0 failed with error -5"
That message is normal for unhandled interfaces.
Does it actually prevent the device from working?
Regards,
Clemens
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