[alsa-devel] Splitting out controls

[Keyon]

On 2015年10月13日 15:07, David Henningsson wrote:
>
>
> On 2015-10-12 22:59, James Cameron wrote:
>> On Mon, Oct 12, 2015 at 02:49:46PM +0100, Liam Girdwood wrote:
>>> I've written up the minutes here below
>>
>> Thanks!
>>
>>> Splitting out controls: Takashi
>>> ===============================
>>>
>>>   - Restricted access.  Consensus to restrict access to some 
>>> controls due
>>> to possibility of breaking HW at kernel level. i.e. prevent feeding
>>> digital Mic into HP amp to prevent speaker over heating.
>>
>> I'd like that.  rt5631.  Avoiding at the moment by removing the 
>> controls.
>
> IIRC, the debate was over "do not expose dangerous controls to 
> userspace at all" vs "expose dangerous controls controls only to root".
>
> I'm strongly voting for "do not expose to userspace at all".
>
> I personally believe that if the physical hardware can be set to state 
> where it's bricked, the hardware itself is buggy.
>
> If the hardware is buggy, this should be worked around in BIOS or 
> whatever firmware is present on the machine. Otherwise there is a bug 
> in BIOS.
>
> If BIOS is buggy and cannot protect the machine from being physically 
> damaged, then we need to work around that in the kernel. Otherwise 
> there is a bug in the kernel.
>
> And if the kernel is buggy, we should fix the kernel. Period. :-)
I agree that also we don't expose dangerous controls at all, or expose 
but do some restraining at codec driver side, e.g. changing dangerous 
setting to save one.
We *cannot* make sure 'root' may know the detail about it and leave the 
risk to him. :)

~Keyon