From: Mauro Carvalho Chehab <mchehab@redhat.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Kay Sievers <kay@vrfy.org>,
Lennart Poettering <lennart@poettering.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Kay Sievers <kay@redhat.com>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
Michael Krufky <mkrufky@linuxtv.org>
Subject: Re: udev breakages - was: Re: Need of an ".async_probe()" type of callback at driver's core - Was: Re: [PATCH] [media] drxk: change it to use request_firmware_nowait()
Date: Wed, 03 Oct 2012 11:12:48 -0300 [thread overview]
Message-ID: <506C47E0.5000600@redhat.com> (raw)
In-Reply-To: <20121002222333.GA32207@kroah.com>
Em 02-10-2012 19:23, Greg KH escreveu:
> On Tue, Oct 02, 2012 at 03:12:39PM -0700, Greg KH wrote:
>> On Tue, Oct 02, 2012 at 09:33:03AM -0700, Linus Torvalds wrote:
>>> I don't know where the problem started in udev, but the report I saw
>>> was that udev175 was fine, and udev182 was broken, and would deadlock
>>> if module_init() did a request_firmware(). That kind of nested
>>> behavior is absolutely *required* to work, in order to not cause
>>> idiotic problems for the kernel for no good reason.
>>>
>>> What kind of insane udev maintainership do we have? And can we fix it?
>>>
>>> Greg, I think you need to step up here too. You were the one who let
>>> udev go. If the new maintainers are causing problems, they need to be
>>> fixed some way.
>>
>> I've talked about this with Kay in the past (Plumbers conference I
>> think) and I thought he said it was all fixed in the latest version of
>> udev so there shouldn't be any problems anymore with this.
>>
>> Mauro, what version of udev are you using that is still showing this
>> issue?
>>
>> Kay, didn't you resolve this already? If not, what was the reason why?
>
> Hm, in digging through the udev tree, the only change I found was this
> one:
>
> commit 39177382a4f92a834b568d6ae5d750eb2a5a86f9
> Author: Kay Sievers <kay@vrfy.org>
> Date: Thu Jul 19 12:32:24 2012 +0200
>
> udev: firmware - do not cancel requests in the initrd
>
> diff --git a/src/udev/udev-builtin-firmware.c b/src/udev/udev-builtin-firmware.c
> index 56dc8fc..de93d7b 100644
> --- a/src/udev/udev-builtin-firmware.c
> +++ b/src/udev/udev-builtin-firmware.c
> @@ -129,7 +129,13 @@ static int builtin_firmware(struct udev_device *dev, int argc, char *argv[], boo
> err = -errno;
> } while (err == -ENOENT);
> rc = EXIT_FAILURE;
> - set_loading(udev, loadpath, "-1");
> + /*
> + * Do not cancel the request in the initrd, the real root might have
> + * the firmware file and the 'coldplug' run in the real root will find
> + * this pending request and fulfill or cancel it.
> + * */
> + if (!in_initrd())
> + set_loading(udev, loadpath, "-1");
> goto exit;
> }
>
>
> which went into udev release 187 which I think corresponds to the place
> when people started having problems, right Mauro?
I'm using here udev-182.
> If so, Mauro, is the solution just putting the firmware into the initrd?
I don't think that putting firmware on initrd is something that we want to
for media drivers. None of the webcam drivers currently need a firmware;
those are required on more complex devices (typically digital TV ones).
While there are a number of PCI devices that require firmware, in practice,
we're seeing more people using USB devices. IMO, it doesn't make any sense
that a hot-pluggable USB device to require a firmware at initrd/initramfs,
with is available only at boot time.
> No wait, it looks like this change was trying to fix the problem where
> firmware files were not in the initrd, so it would stick around for the
> real root to show up so that they could be loaded.
>
> So this looks like it was fixing firmware loading problems for people?
I'll run some tests with this patch applied and see what happens.
> Kay, am I just looking at the totally wrong place here, and this file in
> udev didn't have anything to do with the breakage?
>
> thanks,
>
> greg k-h
>
next prev parent reply other threads:[~2012-10-03 14:13 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1340285798-8322-1-git-send-email-mchehab@redhat.com>
[not found] ` <4FE37194.30407@redhat.com>
[not found] ` <4FE8B8BC.3020702@iki.fi>
[not found] ` <4FE8C4C4.1050901@redhat.com>
[not found] ` <4FE8CED5.104@redhat.com>
[not found] ` <20120625223306.GA2764@kroah.com>
[not found] ` <4FE9169D.5020300@redhat.com>
2012-10-02 13:03 ` udev breakages - was: Re: Need of an ".async_probe()" type of callback at driver's core - Was: Re: [PATCH] [media] drxk: change it to use request_firmware_nowait() Mauro Carvalho Chehab
2012-10-02 16:33 ` Linus Torvalds
2012-10-02 21:03 ` Ivan Kalvachev
2012-10-02 22:37 ` Linus Torvalds
2012-10-03 22:15 ` Lucas De Marchi
2012-10-11 18:33 ` Shea Levy
2012-10-12 1:55 ` Ming Lei
2012-10-02 22:12 ` Greg KH
2012-10-02 22:23 ` Greg KH
2012-10-02 22:47 ` Linus Torvalds
2012-10-03 0:01 ` Jiri Kosina
2012-10-03 0:12 ` Linus Torvalds
2012-10-04 14:36 ` Jiri Kosina
2012-10-03 15:13 ` Mauro Carvalho Chehab
2012-10-03 16:38 ` Linus Torvalds
2012-10-03 17:00 ` Linus Torvalds
2012-10-03 17:09 ` Al Viro
2012-10-03 17:32 ` Linus Torvalds
2012-10-03 19:26 ` Al Viro
2012-10-04 0:57 ` udev breakages - Nix
2012-10-04 10:35 ` Nix
2012-10-03 19:50 ` udev breakages - was: Re: Need of an ".async_probe()" type of callback at driver's core - Was: Re: [PATCH] [media] drxk: change it to use request_firmware_nowait() Greg KH
2012-10-03 20:39 ` Linus Torvalds
2012-10-03 21:04 ` Kay Sievers
2012-10-03 21:05 ` Greg KH
2012-10-03 21:18 ` Kay Sievers
2012-10-03 21:45 ` Alan Cox
2012-10-03 21:58 ` Lucas De Marchi
2012-10-03 22:17 ` Linus Torvalds
2012-10-03 22:48 ` Andy Walls
2012-10-03 22:58 ` Linus Torvalds
2012-10-04 2:39 ` Kay Sievers
2012-10-04 17:29 ` udev breakages - Eric W. Biederman
2012-10-04 17:42 ` Greg KH
2012-10-04 19:17 ` Alan Cox
2012-10-10 3:19 ` Felipe Contreras
2012-10-10 16:08 ` Geert Uytterhoeven
2012-10-11 3:32 ` Eric W. Biederman
2012-10-04 13:39 ` udev breakages - was: Re: Need of an ".async_probe()" type of callback at driver's core - Was: Re: [PATCH] [media] drxk: change it to use request_firmware_nowait() Josh Boyer
2012-10-04 13:58 ` Greg KH
2012-10-03 22:53 ` Stephen Rothwell
2012-10-03 21:10 ` Andy Walls
2012-10-03 19:48 ` Access files from kernel Kirill A. Shutemov
2012-10-03 20:32 ` Linus Torvalds
[not found] ` <CACVXFVNTZmG+zTQNi9mCn9ynsCjkM084TmHKDcYYggtqLfhqNQ@mail.gmail.com>
2012-10-04 1:42 ` udev breakages - was: Re: Need of an ".async_probe()" type of callback at driver's core - Was: Re: [PATCH] [media] drxk: change it to use request_firmware_nowait() Linus Torvalds
2012-10-03 14:12 ` Mauro Carvalho Chehab [this message]
2012-10-03 14:36 ` Kay Sievers
2012-10-03 14:44 ` Linus Torvalds
2012-10-03 16:57 ` Greg KH
2012-10-03 17:24 ` Kay Sievers
2012-10-03 18:07 ` Linus Torvalds
2012-10-03 19:46 ` Mauro Carvalho Chehab
[not found] <fa.90I1W/wmSTgRFXVG67o7Pp3+rKA@ifi.uio.no>
[not found] ` <fa.Oszo+r/ZqdTxC2FHqqg+CRVMJ5Y@ifi.uio.no>
[not found] ` <fa.CoxzZZId9dJONv353c+pFG/HO8E@ifi.uio.no>
[not found] ` <fa.ixJ/7D7BnMK8xp7CwikX7jbmnKU@ifi.uio.no>
[not found] ` <fa./ubRQE7P/T+ateohnOKdDxOFhL4@ifi.uio.no>
[not found] ` <fa.lpiFTa5CtuIkUf2Z5eJ0YlsNwYI@ifi.uio.no>
2012-10-04 14:50 ` Kurt H Maier
2012-10-05 8:03 ` Emmanuel Benisty
2012-10-05 20:17 ` david
2012-10-05 21:43 ` Henrique de Moraes Holschuh
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