From: Matthew Garrett <mjg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jack Stone <jwjstone@fastmail.fm>,
Alan Stern <stern@rowland.harvard.edu>,
Oliver Neukum <oliver@neukum.org>, Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Larry Finger <Larry.Finger@lwfinger.net>,
Chaoming Li <chaoming_li@realsil.com.cn>,
"John W. Linville" <linville@tuxdriver.com>,
Greg Kroah-Hartman <gregkh@suse.de>,
USB list <linux-usb@vger.kernel.org>,
Linux Wireless List <linux-wireless@vger.kernel.org>
Subject: Re: loading firmware while usermodehelper disabled.
Date: Mon, 2 Jan 2012 21:50:28 +0000 [thread overview]
Message-ID: <20120102215028.GA15701@srcf.ucam.org> (raw)
In-Reply-To: <CA+55aFwJuuvqcsgHnZ4-VhUhbVvL6beKogo1adgYyZt_ZM=H7A@mail.gmail.com>
On Mon, Jan 02, 2012 at 01:27:03PM -0800, Linus Torvalds wrote:
> If we didn't load the firmware before the suspend, then the resume
> function of a device sure as hell had better not load it at resume
> time either.
If the hardware has lost its state then refusing to load the firmware at
resume time isn't going to leave you with a working device.
> And for chrissake, don't bother making it more complicated than it is,
> just for some theoretical hardware or situation that nobody cares
> about.
It's not theoretical hardware. This appears to be the current behaviour
of the isight devices. If you reboot they retain their firmware. If you
suspend, they don't. So if we have a flow like this:
1) user boots from cold. Device comes up with generic USB ID.
2) isight_firmware loads and binds. Firmware is loaded. Device
disconnects and reconnects with an ID that's bound by the UVC driver.
3) user reboots. Device comes up with UVC ID. isight_firmware doesn't
bind.
4) user suspends.
5) user resumes. isight_firmware binds and attempts to load firmware.
then just caching the firmware is inadequate - we had never previously
seen the device on this boot, so we've never loaded it in order to cache
it. isight_firmware could unconditionally load the firmware on module
load just in case a device is plugged in, but that seems even less
elegant than caching it.
Now this is obviously somewhat mitigated because isight_firmware won't
have been autoloaded at (3), so won't be there at (5) unless the user's
manually loaded it. But insmodding a driver shouldn't result in stuff
breaking later.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2012-01-02 21:50 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-30 23:54 loading firmware while usermodehelper disabled Dave Jones
2011-12-31 0:22 ` Linus Torvalds
2011-12-31 0:40 ` Matthew Garrett
2011-12-31 15:33 ` Alan Stern
2011-12-31 15:59 ` Oliver Neukum
2012-01-01 2:21 ` Alan Stern
2012-01-01 12:22 ` Oliver Neukum
2012-01-01 16:17 ` Alan Stern
2012-01-01 16:25 ` Michael Büsch
2012-01-01 20:30 ` Linus Torvalds
2012-01-01 21:27 ` Oliver Neukum
2012-01-01 21:39 ` Michael Büsch
2012-01-02 3:33 ` Matthew Garrett
2012-01-02 7:56 ` Oliver Neukum
2012-01-02 4:17 ` Marek Vasut
2012-01-02 5:35 ` Gábor Stefanik
2012-01-02 8:38 ` Marek Vasut
2012-01-02 16:54 ` Alan Stern
2012-01-02 20:41 ` Jack Stone
2012-01-02 20:48 ` Linus Torvalds
2012-01-02 20:55 ` Jack Stone
2012-01-02 21:00 ` Linus Torvalds
2012-01-02 21:09 ` Jack Stone
2012-01-02 21:23 ` Linus Torvalds
2012-01-02 21:31 ` Jack Stone
2012-01-02 21:52 ` Marek Vasut
2012-01-02 21:57 ` Jack Stone
2012-01-02 22:31 ` Marek Vasut
2012-01-02 23:25 ` Jack Stone
2012-01-03 0:31 ` Marek Vasut
2012-01-03 0:44 ` Jack Stone
2012-01-03 0:58 ` Alan Cox
2012-01-03 7:17 ` Marek Vasut
2012-01-03 7:41 ` Oliver Neukum
2012-01-03 0:35 ` Alan Cox
2012-01-03 0:50 ` Alan Cox
2012-01-02 21:19 ` Matthew Garrett
2012-01-02 21:26 ` Jack Stone
2012-01-03 0:42 ` Alan Cox
2012-01-03 11:57 ` Oliver Neukum
2012-01-03 12:19 ` Jack Stone
2012-01-03 13:20 ` Alan Cox
2012-01-03 13:30 ` Oliver Neukum
2012-01-03 13:36 ` Alan Cox
2012-01-02 21:27 ` Linus Torvalds
2012-01-02 21:50 ` Matthew Garrett [this message]
2012-01-02 22:03 ` Linus Torvalds
2012-01-02 22:12 ` Matthew Garrett
2012-01-02 22:19 ` Linus Torvalds
2012-01-02 22:29 ` Matthew Garrett
2012-01-02 22:46 ` Linus Torvalds
2012-01-02 23:00 ` Matthew Garrett
2012-01-02 23:31 ` Jack Stone
2012-01-03 0:13 ` Matthew Garrett
2012-01-03 0:20 ` Alan Cox
2012-01-03 0:37 ` Matthew Garrett
2012-01-03 0:22 ` Jack Stone
2012-01-03 0:31 ` Alan Cox
2012-01-03 0:41 ` Jack Stone
2012-01-03 0:38 ` Matthew Garrett
2012-01-03 0:47 ` Alan Cox
2012-01-03 0:18 ` Alan Cox
2012-01-03 8:26 ` Ingo Molnar
2012-01-03 2:45 ` Alan Stern
2012-01-03 3:25 ` Matthew Garrett
2012-01-03 5:53 ` Linus Torvalds
2012-01-03 11:50 ` Oliver Neukum
2012-01-03 15:16 ` Alan Stern
2012-01-03 12:24 ` Matthew Garrett
2012-01-03 16:29 ` Linus Torvalds
2012-01-03 15:09 ` Alan Stern
2012-01-03 9:16 ` Alexander E. Patrakov
2012-01-03 9:16 ` Alexander E. Patrakov
2012-01-03 9:24 ` david
2012-01-03 13:43 ` Alan Cox
2012-01-03 14:12 ` Bernd Petrovitsch
2012-01-03 0:00 ` Alan Cox
2012-01-02 23:50 ` Alan Cox
2012-01-02 23:53 ` Alan Cox
2011-12-31 16:27 ` Matthew Garrett
2011-12-31 14:20 ` Martin Schleier
2011-12-31 18:39 ` Marek Vasut
2012-01-01 9:48 ` Oliver Neukum
2012-01-01 9:54 ` Marek Vasut
2012-01-01 12:28 ` Oliver Neukum
2012-01-01 16:32 ` Marek Vasut
2012-01-01 17:06 ` Marek Vasut
2012-01-01 20:39 ` Alan Cox
2012-01-01 20:50 ` Michael Büsch
2012-01-02 3:24 ` Marek Vasut
2012-01-02 3:29 ` Marek Vasut
2012-01-01 3:49 ` Larry Finger
2012-01-01 22:45 ` Jack Stone
-- strict thread matches above, loose matches on Subject: below --
2011-12-31 15:01 drahemmaps
2011-12-31 19:29 ` Linus Torvalds
2011-12-31 20:15 ` Matthew Garrett
2011-12-31 20:26 ` Linus Torvalds
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