linux-kernel - Re: [RFC PATCH 12/13] driver core: firmware loader: use small timeout for cache device firmware

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Date:	Sat, 28 Jul 2012 21:58:39 +0800
From:	Ming Lei <ming.lei@...onical.com>
To:	Borislav Petkov <bp@...64.org>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 12/13] driver core: firmware loader: use small timeout
 for cache device firmware

On Fri, Jul 27, 2012 at 6:35 PM, Borislav Petkov <bp@...64.org> wrote:
> On Fri, Jul 27, 2012 at 09:54:25AM +0800, Ming Lei wrote:
>> On Fri, Jul 27, 2012 at 1:54 AM, Borislav Petkov <bp@...64.org> wrote:
>>
>> >> No, it is not what I was saying.
>>
>> I just mean the point is not mentioned in my commit log, but I admit it should
>> be a appropriate cause.
>>
>> >
>> > Ok, maybe I'm not understanding this then. So explain to me this: why
>> > do you need that timeout value of 10, how did we decide it to be 10
>>
>> If one firmware image was loaded successfully before, the probability of
>> loading it successfully at this time should be much higher than the 1st time
>> because something crazy(for example, the firmware is deleted) happens
>> with low probability.
>
> Believe it or not, I'm addressing exactly the possibility of the
> firmware disappearing from under us in the AMD microcode driver
> currently :) (and some other annoyances, of course).

Of course, it is possible since user can delete it anytime, but with very
low probability.

>
>> Choosing 10 secs is just a estimation for loading time because the maximum
>> size of firmware in current distributions is about 2M bytes, since we know
>> it has been loaded successfully before.
>
> This is exactly the comment we want over the code to explain to others
> why we're choosing 10 secs. Simply add that sentence above the 10s
> assignment and we're perfect! :-)

OK, will add the comments in -v1.

Thanks,
--
Ming Lei
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