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SubjectRe: firmware_class warnings on resume
On Mon, Dec 21, 2015 at 9:54 AM, Laura Abbott <labbott@redhat.com> wrote:
> On 12/20/2015 04:20 AM, Andy Lutomirski wrote:
>>
>> I hit this warning fairly frequently when resuming 4.4-rc5:
>>
>> ret = usermodehelper_read_trylock();
>> if (WARN_ON(ret)) {
>> dev_err(device, "firmware: %s will not be loaded\n",
>> name);
>> goto out;
>> }
>>
>> It seems like it could be improved in two ways fairly easily:
>>
>> 1. Shouldn't firmware_class try the direct load before trying to get
>> the usermodehelper lock?
>>
>> 2. Why is the !NOWAIT case doing a trylock? That seems wrong.
>>
>> --Andy
>>
>
> I saw the same warning coming from the bluetooth stack, see the thread
> http://article.gmane.org/gmane.linux.kernel/1950940 and
> http://article.gmane.org/gmane.linux.kernel/1940130.
> At least in the bluetooth case, the conclusion was the firmware request
> should not be happening at that point in time and the reset_resume function
> should be implemented instead. I put that work aside and haven't picked
> it up again.

That's exactly the issue I'm seeing, and I think you're right.

Still, I think the firmware_class code is wrong, too. If it wants to
warn, it should warn that firmware was requested too early in resume.
Using trylock as an excuse to fail a firmware load seems completely
bogus to me.

>
> Thanks,
> Laura



--
Andy Lutomirski
AMA Capital Management, LLC


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