From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jaroslav Kysela <perex@suse.cz>
Cc: Russell King <rmk+lkml@arm.linux.org.uk>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: can device drivers return non-ram via vm_ops->nopage?
Date: Mon, 22 Mar 2004 15:43:00 +1100 [thread overview]
Message-ID: <1079930580.911.176.camel@gaston> (raw)
In-Reply-To: <Pine.LNX.4.58.0403202038530.1816@pnote.perex-int.cz>
On Sun, 2004-03-21 at 06:44, Jaroslav Kysela wrote:
> On Sat, 20 Mar 2004, Russell King wrote:
>
> > It is well known that virt_to_page() is only valid on virtual addresses
> > which correspond to kernel direct mapped RAM pages, and undefined on
> > everything else. Unfortunately, ALSA has been using it with
> > pci_alloc_consistent() for a long time, and this behaviour is what
> > makes ALSA broken. The fact it works on x86 is merely incidental.
>
> It works on PPC as well (at least we have no error reports).
It works only on PPCs that have consistent IOs, not embedded ones which
will use special mappings for getting non-cacheable pages.
> Yes, I'm sorry about that, but the ->nopage usage was requested by Jeff
> Garzik and we're not gurus for the VM stuff. Because we're probably first
> starting using of this mapping scheme, it resulted to problems.
next prev parent reply other threads:[~2004-03-22 4:57 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-20 13:30 can device drivers return non-ram via vm_ops->nopage? Andrea Arcangeli
2004-03-20 14:40 ` William Lee Irwin III
2004-03-20 15:06 ` Andrea Arcangeli
2004-03-20 15:27 ` William Lee Irwin III
2004-03-20 15:44 ` Russell King
2004-03-20 15:57 ` Andrea Arcangeli
2004-03-20 16:15 ` Russell King
2004-03-20 16:25 ` Andrea Arcangeli
2004-03-20 16:57 ` William Lee Irwin III
2004-03-20 17:48 ` Andrea Arcangeli
2004-03-20 19:03 ` Andrea Arcangeli
2004-03-20 15:58 ` Jaroslav Kysela
2004-03-20 16:09 ` Russell King
2004-03-20 19:44 ` Jaroslav Kysela
2004-03-20 22:23 ` Russell King
2004-03-20 22:45 ` William Lee Irwin III
2004-03-20 23:54 ` Russell King
2004-03-21 0:22 ` Zwane Mwaikambo
2004-03-22 4:46 ` Benjamin Herrenschmidt
2004-03-22 18:23 ` Richard Curnow
2004-03-21 0:23 ` William Lee Irwin III
2004-03-21 9:52 ` Arjan van de Ven
2004-03-21 10:39 ` Jaroslav Kysela
2004-03-22 4:43 ` Benjamin Herrenschmidt [this message]
2004-03-20 20:13 ` Andrew Morton
2004-03-20 20:28 ` Andrea Arcangeli
2004-03-20 20:50 ` William Lee Irwin III
2004-03-20 22:26 ` Russell King
2004-03-20 22:45 ` William Lee Irwin III
2004-03-21 20:45 ` David Woodhouse
2004-03-21 20:49 ` Christoph Hellwig
2004-03-21 20:57 ` David Woodhouse
2004-03-21 21:53 ` Linus Torvalds
2004-03-21 22:17 ` Jeff Garzik
2004-03-21 22:23 ` David Woodhouse
2004-03-21 22:23 ` Russell King
2004-03-21 22:34 ` Jeff Garzik
2004-03-21 22:42 ` David Woodhouse
2004-03-21 23:06 ` Jeff Garzik
2004-03-21 22:51 ` Russell King
2004-03-21 23:09 ` Jeff Garzik
2004-03-21 23:11 ` Linus Torvalds
2004-03-21 23:22 ` Jeff Garzik
2004-03-21 23:51 ` Linus Torvalds
2004-03-21 23:58 ` Russell King
2004-03-22 0:34 ` Andrea Arcangeli
2004-03-22 3:05 ` Linus Torvalds
2004-03-23 17:59 ` Andy Whitcroft
2004-03-23 17:58 ` David Woodhouse
2004-03-23 18:11 ` William Lee Irwin III
2004-03-22 0:02 ` David Woodhouse
2004-03-22 3:28 ` Linus Torvalds
2004-03-22 0:10 ` Jeff Garzik
2004-03-22 0:20 ` Russell King
2004-03-22 0:33 ` Jeff Garzik
2004-03-22 4:57 ` Benjamin Herrenschmidt
2004-03-21 23:45 ` Russell King
2004-03-22 0:23 ` William Lee Irwin III
2004-03-22 0:29 ` Jeff Garzik
2004-03-22 1:28 ` William Lee Irwin III
2004-03-22 6:36 ` William Lee Irwin III
2004-03-20 17:39 ` Linus Torvalds
2004-03-20 17:56 ` Andrea Arcangeli
2004-03-20 18:22 ` William Lee Irwin III
2004-03-21 3:13 ` Chris Wedgwood
2004-03-21 6:23 ` Christoph Hellwig
2004-03-21 7:00 ` Chris Wedgwood
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