[alsa-devel] [PATCH] ALSA: usb-audio: Fix UAC2 get_ctl request with a RANGE attribute

[Kirill Marinushkin]

Hello maintainers of <stable at vger.kernel.org>,


As discussed earlier in this thread, I propose this patch to stable.

It fixes the issue, which exists since v2.6.34.


Best Regards,

Kirill

On 02/12/18 09:08, Takashi Iwai wrote:
> On Thu, 08 Feb 2018 07:21:36 +0100,
> Kirill Marinushkin wrote:
>> On 02/07/18 06:45, Takashi Iwai wrote:
>>> On Mon, 29 Jan 2018 06:37:55 +0100,
>>> Kirill Marinushkin wrote:
>>>> The layout of the UAC2 Control request and response varies depending on
>>>> the request type. With the current implementation, only the Layout 2
>>>> Parameter Block (with the 2-byte sized RANGE attribute) is handled
>>>> properly. For the Control requests with the 1-byte sized RANGE attribute
>>>> (Bass Control, Mid Control, Tremble Control), the response is parsed
>>>> incorrectly.
>>>>
>>>> This commit:
>>>> * fixes the wLength field value in the request
>>>> * fixes parsing the range values from the response
>>>>
>>>> Fixes: 23caaf19b11e ("ALSA: usb-mixer: Add support for Audio Class v2.0")
>>>> Signed-off-by: Kirill Marinushkin <k.marinushkin at gmail.com>
>>>> Cc: Jaroslav Kysela <perex at perex.cz>
>>>> Cc: Takashi Iwai <tiwai at suse.com>
>>>> Cc: Jaejoong Kim <climbbb.kim at gmail.com>
>>>> Cc: Bhumika Goyal <bhumirks at gmail.com>
>>>> Cc: Stephen Barber <smbarber at chromium.org>
>>>> Cc: Julian Scheel <julian at jusst.de>
>>>> Cc: alsa-devel at alsa-project.org
>>>> Cc: linux-kernel at vger.kernel.org
>>> Sorry for the late reply, as I've been (and still) off.
>>>
>>> Does this bug actually hit on any real devices, or is it only a
>>> logical error so far?  In the former case, a Cc to stable is
>>> mandatory.
>>>
>>> In anyway, I'll review and merge it properly once after I back to
>>> work.
>>>
>>>
>>> thanks,
>>>
>>> Takashi
>> Hello Takashi,
>>
>> Thank you for your answer. I will wait until you are back to work, don't 
>> worry about the late replies.
>>
>> I did not hit the issue on a real device.
>>
>> During my UAC2 experiments, I reproduced this issue on the development 
>> board, and then tested my solution on it.
> OK, if it happened on a development system, it's a real issue, and we
> should put Cc to stable.  Now I applied the patch.
>
> Thanks!
>
>
> Takashi