[alsa-devel] [PATCH] ALSA: usb-audio: Fix the enable parameter behavior

[Tamaki Nishino]

Hi Takashi,
Thanks for your feedback.

I'm sorry but I didn't know the origin of the enable option.
So is it acceptable like
---
Change the semantics of the enable option for snd-usb-audio

This patch changes the semantics of the enable option for snd-usb-audio
in order to allow users to disable a device specified by either or both of the
vendor id and the product id.
---

I would appreciate for your any feedback in advance.

Best regards,

Tamaki

On Thu, Nov 30, 2017 at 6:06 PM, Takashi Iwai <tiwai at suse.de> wrote:
> On Wed, 29 Nov 2017 23:26:16 +0100,
> Tamaki Nishino wrote:
>>
>> The enable parameter doesn't seem to work as expected. Even when the
>> enable parameter is set to false in /etc/modprobe.d/alsa-base.conf like
>> "options snd-usb-audio index=-2 vid=0x1415 pid=0x1d27 enable=0",
>> the specified device is not disabled.
>>
>> This patch fixes the enable parameter behavior to disable the device
>> correctly.
>
> Heh, strictly speaking, this is no "fix".  The behavior of the current
> enable option is "correct", per se; it disables the first-defined
> slot, and in the case of USB-audio, the probe continues to the next
> slot as it's a hot-plug device.
>
> OTOH, it's just badly designed, and the option is present just for
> compatibility with other modules -- e.g. YaST has put enable option
> always when configuring manually.
>
> So, I find it OK to change the semantics of this option, as it's
> practically useless, and the breakage is very unlikely.
> But please make it clear that the patch is rather to improve the
> usability, not about the correctness.
>
>
> thanks,
>
> Takashi