From: James Bottomley <James.Bottomley@SteelEye.com>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: linux-arch@vger.kernel.org, Jeff Garzik <jgarzik@pobox.com>,
Russell King <rmk@arm.linux.org.uk>,
Linus Torvalds <torvalds@osdl.org>,
David Woodhouse <dwmw2@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
Andrew Morton <akpm@osdl.org>, Andrea Arcangeli <andrea@suse.de>
Subject: Re: can device drivers return non-ram via vm_ops->nopage?
Date: 21 Mar 2004 23:56:40 -0500 [thread overview]
Message-ID: <1079931403.5345.74.camel@mulgrave> (raw)
In-Reply-To: <20040322044615.GC2045@holomorphy.com>
On Sun, 2004-03-21 at 23:46, William Lee Irwin III wrote:
> Okay, this is bad news for sound (and possibly some graphics) drivers
> on PA-RISC, since this mapping of coherent areas into userspace is
> exactly what they're trying to do for the device interfaces they
> export to the user.
>
> Are you seeing breakage there, or are the drivers doing this
> unused on PA-RISC?
Well, our older sound drivers have never worked since ALSA (they hang
off the GSC bus which ALSA doesn't have an abstraction for). Mostly we
use serial console, and a HP specific thing called a STI framebuffer for
video.
The problems I describe only occur if you try to mmap coherent memory.
mmaping streaming memory is fine.
But, I would expect that any arch with a virtually indexed cache would
have similar problems: there may be many address aliases in the cache
and the DMA controller probably only knows about one of them.
James
next prev parent reply other threads:[~2004-03-22 4:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20040321204931.A11519@infradead.org>
[not found] ` <1079902670.17681.324.camel@imladris.demon.co.uk>
[not found] ` <Pine.LNX.4.58.0403211349340.1106@ppc970.osdl.org>
[not found] ` <20040321222327.D26708@flint.arm.linux.org.uk>
[not found] ` <405E1859.5030906@pobox.com>
[not found] ` <20040321225117.F26708@flint.arm.linux.org.uk>
[not found] ` <Pine.LNX.4.58.0403211504550.1106@ppc970.osdl.org>
[not found] ` <20040321234515.G26708@flint.arm.linux.org.uk>
[not found] ` <20040322002349.GZ2045@holomorphy.com>
[not found] ` <405E3387.1050505@pobox.com>
2004-03-22 3:45 ` can device drivers return non-ram via vm_ops->nopage? William Lee Irwin III
2004-03-22 4:41 ` James Bottomley
2004-03-22 4:46 ` William Lee Irwin III
2004-03-22 4:56 ` James Bottomley [this message]
2004-03-22 5:26 ` Benjamin Herrenschmidt
2004-03-22 11:58 ` Andrea Arcangeli
2004-03-22 12:05 ` Russell King
2004-03-22 12:34 ` Andrea Arcangeli
2004-03-22 9:30 ` Russell King
2004-03-22 15:04 ` James Bottomley
2004-03-22 15:15 ` Russell King
2004-03-22 15:27 ` James Bottomley
2004-03-22 21:50 ` Benjamin Herrenschmidt
2004-03-22 22:18 ` Jeff Garzik
2004-03-22 22:35 ` William Lee Irwin III
2004-03-22 23:57 ` Benjamin Herrenschmidt
2004-03-23 0:22 ` David Woodhouse
2004-03-23 2:07 ` William Lee Irwin III
2004-03-23 9:28 ` Russell King
2004-03-23 9:34 ` David Woodhouse
2004-03-23 10:04 ` Russell King
2004-03-23 10:05 ` William Lee Irwin III
2004-03-23 11:29 ` Benjamin Herrenschmidt
2004-03-23 11:35 ` Andrea Arcangeli
2004-03-23 11:44 ` William Lee Irwin III
2004-03-23 12:34 ` Andrea Arcangeli
2004-03-23 12:40 ` Russell King
2004-03-23 15:25 ` Linus Torvalds
2004-03-23 15:36 ` Andrea Arcangeli
2004-03-23 15:46 ` Linus Torvalds
2004-03-23 15:50 ` Russell King
2004-03-23 22:10 ` Benjamin Herrenschmidt
2004-03-25 20:25 ` Russell King
2004-03-28 10:17 ` Russell King
2004-03-23 12:49 ` William Lee Irwin III
2004-03-22 23:19 ` Russell King
2004-03-22 23:35 ` Jeff Garzik
2004-03-23 2:26 ` James Bottomley
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1079931403.5345.74.camel@mulgrave \
--to=james.bottomley@steeleye.com \
--cc=akpm@osdl.org \
--cc=andrea@suse.de \
--cc=dwmw2@infradead.org \
--cc=hch@infradead.org \
--cc=jgarzik@pobox.com \
--cc=linux-arch@vger.kernel.org \
--cc=rmk@arm.linux.org.uk \
--cc=torvalds@osdl.org \
--cc=wli@holomorphy.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox