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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Marek Vasut <marek.vasut@gmail.com>
Cc: Oliver Neukum <oliver@neukum.org>,
	Linus Torvalds <torvalds@linux-foundation.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>,
	Matthew Garrett <mjg@redhat.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: Sun, 1 Jan 2012 20:39:45 +0000	[thread overview]
Message-ID: <20120101203945.0ebc2f55@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <201201011732.23069.marek.vasut@gmail.com>

> > Device IDs can morph due to a power loss. After resumption another driver
> > would bind.
> 
> What do you mean? I don't think I quite follow.

Lots of USB hardware appears as one device id when powered on, then when
the firmware is loaded turns into something else that becomes relevant to
the user.

So on powerup your wireless card goes

	'I've no idea what I am, feed me firmware for this id"

when it gets the firmware it disconnects, reconnects and says

	"I am a USB wireless card with this id"

When you suspend the power gets killed so the device loses its firmware
and goes back to being a firmware requesting thing on resume.

Worse still - you don't easily know if the device is in fact new and was
added while suspended, or was always there.

So for those devices you do need to load the firmware into them
automatically after the resume to work out what they are and get the MAC
to see if its the same wireless card or not.


Alan

  parent reply	other threads:[~2012-01-01 20:39 UTC|newest]

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20111230235421.GA6054@redhat.com>
2011-12-31  0:22 ` loading firmware while usermodehelper disabled 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
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  9:24                               ` 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 [this message]
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

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