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From: Arnd Bergmann <arnd@arndb.de>
To: andy.green@linaro.org
Cc: Linux USB list <linux-usb@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: RFC: Platform data for onboard USB assets
Date: Fri, 11 Mar 2011 13:31:13 +0100	[thread overview]
Message-ID: <201103111331.13932.arnd@arndb.de> (raw)
In-Reply-To: <4D79F068.2080009@linaro.org>

Hi Andy,

On Friday 11 March 2011, Andy Green wrote:
> 
> platform_data is a well established way in Linux to pass configuration 
> data up to on-board assets from a machine file like mach-xyz.c.  It's 
> also supported to pass platform_data up to devices that are probed 
> asynchronously from busses like i2c as well, which is very handy.
> 
> However AFAIK it's not possible to bind platform_data to probed USB 
> devices as it stands.
> 
> There are now boards which have on-board USB assets, for example OMAP4 
> Panda which has a USB <-> Ethernet bridge wired up permanently.  It'd be 
> convenient to also be able to pass optional platform_data to these 
> devices when they are asynchronously probed.

Sorry, but I think it's a bad idea to use platform data for this.
USB is a bus that we can reasonably probe, while we use platform_data
only for stuff that we can by definition not probe at all.

> The particular use that suggested this is on Panda, it would be ideal to 
> be able to set a flag in the usb device's platform data that forces it 
> to be named eth%d since it's a hardwired asset on the board with an RJ45 
> socket.

I understand the problem, but IMHO there really needs to be a better
solution for this. As far as I understand, the underlying problem is
that USB ethernet devices with a proper MAC address get a different
device name from devices with a generated random MAC address, and
the people that designed this board were trying to save a few cents
by not allocating a MAC address for the ethernet device [1], right?

I believe we should fix this particular problem locally, instead of
coming up with generic infrastructure for broken hardware.

One relatively easy solution would be to allow passing a MAC address
to this particular device driver as a module parameter, and generating
a fixed MAC address in the regular vendor space when installing the
boot loader. That would also solve the problem that a DHCP server
currently assigns a new IP address to a panda board at every boot.

	Arnd
---
[1] https://bugs.launchpad.net/linux-linaro/+bug/622429

  reply	other threads:[~2011-03-11 12:31 UTC|newest]

Thread overview: 185+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-11  9:50 RFC: Platform data for onboard USB assets Andy Green
2011-03-11 12:31 ` Arnd Bergmann [this message]
2011-03-11 12:44   ` Andy Green
2011-03-11 14:42     ` Roger Quadros
2011-03-11 15:12       ` Roger Quadros
2011-03-11 15:22       ` Arnd Bergmann
2011-03-11 15:50         ` Roger Quadros
2011-03-11 15:55           ` Arnd Bergmann
2011-03-11 15:29   ` Mark Brown
2011-03-11 15:54     ` Arnd Bergmann
2011-03-11 16:03       ` Mark Brown
2011-03-11 16:14         ` Greg KH
2011-03-11 16:27           ` Mark Brown
2011-03-11 16:35             ` Greg KH
2011-03-11 16:48               ` Mark Brown
2011-03-11 16:56                 ` Greg KH
2011-03-11 17:08                   ` Mark Brown
2011-03-11 17:23                     ` Greg KH
2011-03-11 17:41                       ` Mark Brown
2011-03-17  2:14                       ` Nicolas Pitre
2011-03-17 20:13                         ` Greg KH
2011-03-17 20:18                           ` Mark Brown
2011-03-17 20:26                             ` Greg KH
2011-03-17 21:24                               ` Mark Brown
2011-03-17 21:31                                 ` Greg KH
2011-03-17 21:40                                   ` Mark Brown
2011-03-17 21:47                                     ` Greg KH
2011-03-17 22:33                                       ` Arnd Bergmann
2011-03-17 22:33                                         ` Arnd Bergmann
2011-03-17 22:53                                         ` Greg KH
2011-03-17 22:53                                           ` Greg KH
2011-03-17 23:18                                           ` Andy Green
2011-03-17 23:18                                             ` Andy Green
2011-03-17 23:25                                             ` Greg KH
2011-03-18  7:42                                               ` Andy Green
2011-03-18  7:42                                                 ` Andy Green
2011-03-18 22:54                                                 ` Benjamin Herrenschmidt
2011-03-18 22:54                                                   ` Benjamin Herrenschmidt
2011-03-18 22:57                                                   ` Andy Green
2011-03-18 22:57                                                     ` Andy Green
2011-03-18  4:54                                             ` Grant Likely
2011-03-18  4:54                                               ` Grant Likely
2011-03-18  8:19                                               ` Arnd Bergmann
2011-03-18  8:19                                                 ` Arnd Bergmann
2011-03-17 23:22                                         ` Andy Green
2011-03-18 15:00                                           ` Arnd Bergmann
2011-03-18 15:00                                             ` Arnd Bergmann
2011-03-18 15:15                                             ` Mark Brown
2011-03-18 15:15                                               ` Mark Brown
2011-03-18 17:52                                             ` Andy Green
2011-03-18 17:52                                               ` Andy Green
2011-03-18 18:20                                               ` David Anders
2011-03-18 18:20                                                 ` David Anders
2011-03-18 18:25                                                 ` Mark Brown
2011-03-18 18:25                                                   ` Mark Brown
2011-03-18 20:02                                                   ` Andy Green
2011-03-18 20:02                                                     ` Andy Green
2011-03-18 21:11                                                     ` Arnd Bergmann
2011-03-18 21:17                                                       ` Andy Green
2011-03-18 21:17                                                         ` Andy Green
2011-03-18 20:06                                               ` Arnd Bergmann
2011-03-18 20:06                                                 ` Arnd Bergmann
2011-03-18 21:33                                                 ` Andy Green
2011-03-18 23:25                                                   ` Mark Brown
2011-03-18 23:25                                                     ` Mark Brown
2011-03-18 23:33                                                     ` Andy Green
2011-03-18 23:33                                                       ` Andy Green
2011-03-18 21:36                                                 ` Grant Likely
2011-03-18 21:36                                                   ` Grant Likely
2011-03-18 22:47                                                 ` Benjamin Herrenschmidt
2011-03-18 22:47                                                   ` Benjamin Herrenschmidt
2011-03-18 21:28                                               ` Grant Likely
2011-03-18 21:28                                                 ` Grant Likely
2011-03-18 23:04                                                 ` Andy Green
2011-03-18 23:04                                                   ` Andy Green
2011-03-18 22:37                                           ` Benjamin Herrenschmidt
2011-03-18 22:37                                             ` Benjamin Herrenschmidt
2011-03-18 22:39                                             ` Andy Green
2011-03-18 22:39                                               ` Andy Green
2011-03-17 23:27                                         ` Grant Likely
2011-03-17 23:27                                           ` Grant Likely
2011-03-18  7:49                                           ` Andy Green
2011-03-18  8:25                                             ` Arnd Bergmann
2011-03-18  8:25                                               ` Arnd Bergmann
2011-03-18  8:38                                               ` Andy Green
2011-03-18  8:38                                                 ` Andy Green
2011-03-17 22:11                               ` Arnd Bergmann
2011-03-17 22:20                                 ` Greg KH
2011-03-18  8:42                                 ` Roger Quadros
2011-03-18  9:01                                   ` Arnd Bergmann
2011-03-18  9:55                                     ` Roger Quadros
2011-03-18 10:09                                       ` Andy Green
2011-03-17 21:03                           ` Nicolas Pitre
2011-03-17 21:32                             ` Greg KH
2011-03-11 16:26         ` Andy Green
2011-03-11 16:45           ` Alan Stern
2011-03-11 16:51             ` Andy Green
2011-03-11 17:08               ` Greg KH
2011-03-11 18:09                 ` Andy Green
2011-03-11 19:12                   ` Alan Stern
2011-03-11 20:05                     ` Andy Green
2011-03-11 20:21                       ` Greg KH
2011-03-11 21:07                         ` Andy Green
2011-03-11 21:44                           ` Greg KH
2011-03-11 22:24                             ` Andy Green
2011-03-12 16:00                             ` Alan Stern
2011-03-12 23:02                               ` Andy Green
2011-03-11 19:37                   ` Greg KH
2011-03-11 16:53             ` Mark Brown
2011-03-11 16:08 ` Greg KH
2011-03-11 16:20   ` Andy Green
2011-03-11 16:36     ` Greg KH
2011-03-11 16:41       ` Andy Green
2011-03-11 22:07         ` Benjamin Herrenschmidt
2011-03-11 21:52 ` Benjamin Herrenschmidt
2011-03-11 22:45 ` Grant Likely
2011-03-11 22:47   ` Andy Green
2011-03-11 23:39     ` Grant Likely
2011-03-14 14:54   ` Arnd Bergmann
2011-03-22 15:05 ` Jaswinder Singh
2011-03-22 16:04   ` Andy Green
2011-03-22 18:19     ` Jaswinder Singh
2011-03-22 18:37       ` Andy Green
2011-03-22 18:59         ` Jaswinder Singh
2011-03-22 19:35           ` Andy Green
     [not found] ` <AANLkTim=ezye=1fQP_1a2SWbPnbENP9B+k27Z3AkS=zf@mail.gmail.com>
2011-03-22 15:12   ` Mark Brown
2011-03-22 15:23     ` Jaswinder Singh
2011-03-24 18:56     ` Grant Likely
2011-03-22 21:08   ` Benjamin Herrenschmidt
2011-03-22 22:37     ` Andy Green
2011-03-23  1:03       ` Benjamin Herrenschmidt
2011-03-23  2:26         ` Nicolas Pitre
2011-03-23  3:23           ` Benjamin Herrenschmidt
2011-03-23  4:21             ` Nicolas Pitre
2011-03-23  4:56               ` Greg KH
2011-03-23  5:44               ` Benjamin Herrenschmidt
2011-03-23  9:38               ` Alan Cox
2011-03-23 10:53                 ` Mark Brown
2011-03-23 15:04                   ` Greg KH
2011-03-23 15:10                     ` Mark Brown
2011-03-23 15:24                     ` Andy Green
2011-03-23 15:45                       ` Arnd Bergmann
2011-03-23 15:38                     ` Nicolas Pitre
2011-03-23  9:31             ` Andy Green
2011-03-23  9:47               ` Alan Cox
2011-03-23 10:06                 ` Andy Green
2011-03-23 10:32                   ` Arnd Bergmann
2011-03-23 10:39                     ` Andy Green
2011-03-23 10:56                       ` Alan Cox
2011-03-23 11:13                         ` Andy Green
2011-03-23 11:34                           ` Alan Cox
2011-03-23 12:02                             ` Andy Green
2011-03-23 15:08                     ` Greg KH
2011-03-23 16:12                       ` Arnd Bergmann
2011-03-23 16:22                         ` Greg KH
2011-03-23 16:34                           ` Andy Green
2011-03-23 16:56                           ` [RFC] usbnet: use eth%d name for known ethernet devices Arnd Bergmann
2011-03-23 17:04                             ` Andy Green
2011-03-23 17:11                               ` Arnd Bergmann
2011-03-24 10:45                                 ` Andy Green
2011-03-24 10:45                                   ` Andy Green
2011-03-23 17:13                             ` Arnd Bergmann
2011-03-23 17:54                               ` David Anders
2011-03-23 18:46                             ` Greg KH
2011-03-23 19:35                               ` Arnd Bergmann
     [not found]                                 ` <AANLkTim7hPfTv3gDYnh+jGxHBg0OvX=r1FKYoHnH7H_o@mail.gmail.com>
2011-03-23 19:57                                   ` Arnd Bergmann
2011-03-23 19:59                                     ` Randy Dunlap
2011-03-23 23:17                                       ` Michal Nazarewicz
2011-03-23 23:19                                         ` Randy Dunlap
2011-03-23 23:38                                         ` Steve Calfee
2011-03-24  0:01                                           ` Ben Hutchings
2011-03-24 13:13                                             ` Arnd Bergmann
2011-03-24 13:15                                               ` Arnd Bergmann
2011-03-24 13:44                                                 ` Andy Green
2011-03-24 13:56                                                 ` Alan Stern
2011-03-24 13:56                                                   ` Alan Stern
2011-03-24 17:20                                                 ` Alexey Orishko
2011-03-25 11:57                                                   ` Arnd Bergmann
2011-03-25 16:26                                                     ` Alexey Orishko
2011-03-25 16:43                                                       ` Arnd Bergmann
2011-03-24 19:17                   ` RFC: Platform data for onboard USB assets Grant Likely
2011-03-24 20:10                     ` Andy Green
2011-03-23 14:55                 ` Nicolas Pitre
2011-03-23 10:22               ` Benjamin Herrenschmidt
2011-03-23 15:11                 ` Nicolas Pitre

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