From: Greg KH <greg@kroah.com>
To: Matthew Wilcox <willy@debian.org>
Cc: "Adam J. Richter" <adam@yggdrasil.com>,
andmike@us.ibm.com, hch@lst.de, James.Bottomley@steeleye.com,
linux-kernel@vger.kernel.org, mochel@osdl.org,
parisc-linux@lists.parisc-linux.org
Subject: Re: [parisc-linux] Untested port of parisc_device to generic device interface
Date: Fri, 8 Nov 2002 22:03:42 -0800 [thread overview]
Message-ID: <20021109060342.GA7798@kroah.com> (raw)
In-Reply-To: <20021109052150.T12011@parcelfarce.linux.theplanet.co.uk>
On Sat, Nov 09, 2002 at 05:21:50AM +0000, Matthew Wilcox wrote:
>
> Everyone's saying "ra! ra! generic device model!" without asking
> what the cost is. Don't you think it's reasonable that _as the most
> common device type_, struct device should be able to support PCI in a
> clean manner?
No I do not.
> Don't you think that the fact that it fails to do so is a problem?
Yes I do.
> Don't you look at the locks sprinkled all over the struct device
> system and wonder what they're all _for_?
Nope :)
(yes, I do wonder, and yes, they will be cleaned up...)
> Don't get me wrong. I want a generic device model. But I think it's
> clear the current one has failed to show anything more than eye candy.
> Perhaps it's time to start over, with something small and sane -- maybe
> kobject (it's not quite what we need, but it's close). Put one of those
> in struct pci_dev. Remove duplicate fields. Now maybe grow kobject a
> little, or perhaps start a new struct with a kobject as its first member.
No, lets start pulling stuff out of pci_dev and relying on struct
device. The reason this hasn't happened yet is no one has been willing
to break all of the PCI drivers, yet.
I know Pat is going to be doing this soon, and if he doesn't get to it,
I will. But as Adam said, don't throw away the idea because it looks
crufty now. This has been a _constantly_ evolving model as we work to
get it right. It will take time, and we are still getting there.
> And, for gods sake, don't fuck it up by integrating it with USB too early
> in the game.
In my defense, USB was the _only_ bus willing to step up and try to do
the integration to work the initial kinks out. The SCSI people are
being drug kicking and screaming into it, _finally_ now (hell, SCSI is
still not using the updated PCI interface, those people _never_ update
their drivers if they can avoid it.)
> Let's get it right for PCI, maybe some other internal busses
> (i'm gagging to write an EISA subsystem ;-). SCSI is more interesting
> than USB. Above all, don't fall into the trap of "It's a bus and it
> has devices on it, therefore it must be a part of devicefs".
Sure SCSI's more interesting, to you :)
By having USB be one of the first adopters (after PCI), we have found a
_lot_ of issues and bugs that happened due to devices showing up and
disappearing at odd times. Which was _much_ easier to debug than PCI
would have been. SCSI can't even do hotplug devices _yet_. How would
we have debugged this stuff then?
And yes, USB belongs in the model, if for no other reason, that "it's a
bus and it has devices on it" :)
> *sigh*. halloween was a week ago.
Patches for this stuff are going to be happening for quite some time
now, don't despair.
And they are greatly appreciated, and welcomed from everyone :)
thanks,
greg k-h
next prev parent reply other threads:[~2002-11-09 6:01 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-09 4:51 [parisc-linux] Untested port of parisc_device to generic device interface Adam J. Richter
2002-11-09 5:21 ` Matthew Wilcox
2002-11-09 6:03 ` Greg KH [this message]
2002-11-09 15:33 ` J.E.J. Bottomley
2002-11-13 6:13 ` Greg KH
2002-11-13 7:46 ` Miles Bader
2002-11-13 7:52 ` Greg KH
2002-11-13 8:02 ` Miles Bader
2002-11-13 8:10 ` Greg KH
2002-11-13 8:26 ` Miles Bader
2002-11-13 8:25 ` Greg KH
2002-11-13 9:05 ` Miles Bader
[not found] ` <miles@lsi.nec.co.jp>
2002-11-13 20:13 ` Grant Grundler
2002-11-13 20:21 ` J.E.J. Bottomley
2002-11-13 20:37 ` Grant Grundler
2002-11-13 11:59 ` Ivan Kokshaysky
2002-11-13 12:36 ` Marc Zyngier
2002-11-13 16:32 ` Bjorn Helgaas
2002-11-13 17:23 ` J.E.J. Bottomley
2002-11-13 20:33 ` Grant Grundler
2002-11-13 20:44 ` J.E.J. Bottomley
2002-11-13 21:42 ` Grant Grundler
2002-11-13 20:12 ` Grant Grundler
2002-11-09 7:58 ` Marc Zyngier
2002-11-09 18:04 ` Grant Grundler
-- strict thread matches above, loose matches on Subject: below --
2002-12-18 3:01 [RFT][PATCH] generic device DMA implementation James Bottomley
2002-12-18 3:13 ` David Mosberger
2002-12-28 18:14 ` Russell King
2002-12-28 18:19 ` James Bottomley
2002-12-04 17:47 [RFC] " James Bottomley
2002-12-04 18:27 ` Jeff Garzik
2002-12-04 19:36 ` James Bottomley
2002-12-04 21:19 ` Miles Bader
2002-12-04 21:21 ` Miles Bader
2002-12-04 21:42 ` James Bottomley
2002-12-05 5:44 ` Miles Bader
2002-12-04 21:46 ` James Bottomley
2002-12-05 2:31 ` Miles Bader
2002-12-05 3:06 ` James Bottomley
2002-12-05 5:02 ` David Gibson
2002-12-05 11:15 ` Benjamin Herrenschmidt
2002-12-05 11:16 ` William Lee Irwin III
2002-12-05 15:12 ` James Bottomley
2002-12-05 0:47 ` David Gibson
2002-12-05 0:54 ` Jeff Garzik
2002-12-05 1:44 ` James Bottomley
2002-12-05 2:38 ` David Gibson
2002-12-05 3:13 ` James Bottomley
2002-12-05 5:05 ` David Gibson
2002-12-05 15:03 ` James Bottomley
2002-12-05 23:54 ` David Gibson
2002-12-05 3:17 ` Miles Bader
2002-12-05 6:06 ` David Gibson
2002-12-05 6:43 ` Miles Bader
2002-12-05 23:44 ` David Gibson
2002-12-06 2:23 ` Miles Bader
2002-12-05 3:41 ` Jeff Garzik
2002-12-05 6:04 ` David Gibson
2002-12-05 16:29 ` Jeff Garzik
2002-12-05 23:59 ` David Gibson
2002-12-05 11:08 ` Benjamin Herrenschmidt
2002-12-05 11:35 ` Russell King
2002-12-05 15:24 ` James Bottomley
2002-12-06 0:01 ` David Gibson
2002-11-10 5:20 [parisc-linux] Untested port of parisc_device to generic device interface Adam J. Richter
2002-11-10 1:50 Adam J. Richter
2002-11-10 0:23 Adam J. Richter
2002-11-10 2:01 ` J.E.J. Bottomley
2002-11-10 2:15 ` Matthew Wilcox
2002-11-09 12:22 Adam J. Richter
[not found] <200211090128.RAA31693@adam.yggdrasil.com>
2002-11-09 3:37 ` Matthew Wilcox
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