linux-kernel - Re: [PATCH] firmware loader: don't cancel _nowait requests when helper is not yet available

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Message-ID: <CAPXgP11fWf-0Jkk=d6G+d=sQa-hoX3jUM+K6K4rGYhh0dv1u_w@mail.gmail.com>
Date:	Wed, 14 Mar 2012 00:25:58 +0100
From:	Kay Sievers <kay@...y.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Greg KH <gregkh@...uxfoundation.org>,
	Christian Lamparter <chunkeey@...glemail.com>,
	linux-kernel@...r.kernel.org,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	alan@...rguk.ukuu.org.uk,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Linux PM mailing list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH] firmware loader: don't cancel _nowait requests when
 helper is not yet available

On Tue, Mar 13, 2012 at 20:42, Rafael J. Wysocki <rjw@...k.pl> wrote:
> On Sunday, March 11, 2012, Kay Sievers wrote:
>> On Sat, Mar 10, 2012 at 00:36, Greg KH <gregkh@...uxfoundation.org> wrote:

>> > What does uevent have to do with things here?
>>
>> I don't think that the firmware loader should care about the
>> usermodehelper at all, and that stuff fiddling should just be removed
>> from the firmware class.
>
> It's there to warn people that their drivers do stupid things like
> loading frimware during system resume, which is guaranteed not to work.
>
> IOW, it's there very much on purpose.

Using the /sbin/hotplug is no case that needs any warning. It' such a
broken model these days, that firmware loading is the least problem
that occurs with it.

>> Forking /sbin/hotplug is disabled by default, it is a broken concept,
>> and it cannot work reliably on today's systems.
>>
>> Firmware is not loaded by /sbin/hotplug since many years, but by udev
>> or whatever service handles uevents, like ueventd on android.
>
> Which I'm not sure why is relevant here.

It is relevant in the sense that the firmware loader should not even
know that a uevent *can* cause a usermodehelper exec() if it runs in
legacy mode. The firmware loader just has no business in fiddling with
the details of driver core legacy stuff. I don't think his warning
makes much sense.

Kay
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