Re: [PATCH] Show processing coefficients in codec proc file

[David Henningsson <david.henningsson@canonical.com>]

2010-08-19 22:24, Takashi Iwai skrev:
> At Thu, 19 Aug 2010 20:48:56 +0200,
> David Henningsson wrote:
>>
>> 2010-08-19 20:28, Takashi Iwai skrev:
>>> At Thu, 19 Aug 2010 20:17:42 +0200,
>>> David Henningsson wrote:
>>>>
>>>> This patch is helpful for tracking down bugs without having all
>>>> information about the chip.
>>>
>>> I don't want to change coef index in reading a proc file in general.
>>
>> Good point. But I think the solution to that problem would be to
>> - read current index
>> - do the loop
>> - restore current index
>>
>> ...and perhaps protect that with an appropriate mutex (which one)?
>>
>>> If any, you should implement a codec-specific hook.
>>
>> I'm sorry, but I don't really see how that would help...?
> 
> If it's specific to a codec, then you know whether reading the coef
> in that way can be harmful or not.  It's not only about the race
> via proc file but also the influence of coef on the actual codec
> behavior.

Oh, so there are chips that are *that* broken...

Yet it could be a lifesaver so I wouldn't want to give up on the idea
just yet...

Do you know off the top of your head approximately what codec chips this
is about, where reading a coef (or setting its index) can cause unwanted
side-effects?


-- 
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic