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

[Kirill Marinushkin]

On 02/13/18 06:04, Takashi Iwai wrote:
> On Mon, 12 Feb 2018 20:32:53 +0100,
> Kirill Marinushkin wrote:
>> 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.
> It's already marked in the applied patch, so you don't need to ping
> stable kernel guys.
>
>
> thanks,
>
> Takashi

Hello Takashi,

Thank you for the clarification

Best Regards,
Kirill
>
>>
>> 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