From: "Michel Dänzer" <michel@daenzer.net>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>,
o jordan <ojordan12345@hotmail.co.uk>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: PowerPC radeon KMS - is it possible?
Date: Wed, 18 Apr 2012 12:44:14 +0200 [thread overview]
Message-ID: <1334745854.5989.295.camel@thor.local> (raw)
In-Reply-To: <1334745292.5989.291.camel@thor.local>
On Mit, 2012-04-18 at 12:34 +0200, Michel D=C3=A4nzer wrote:=20
> On Mit, 2012-04-18 at 20:20 +1000, Benjamin Herrenschmidt wrote:=20
> >=20
> > I suspect there's a fundamental design issue with apple bridge in that
> > the CPU to memory path isn't coherent at all with the GPU to memory pat=
h
> > ie. even vs. cache flush instructions (ie buffers in the memory
> > controllers can still be out of sync).
> >=20
> > Darwin does some gross hacks to work around that, some of them visible
> > in the AGP drivers, some burried in the Apple driver, I don't know for
> > sure. It's possible that they end up mapping all AGP memory as cache
> > inhibited, but we can't do that because of our linear mapping.
>=20
> We are doing that though...
This reminded me, I've been running with the patch below, but I'm not
sure it makes any difference. Maybe Andreas or Jordan can try it.
diff --git a/arch/powerpc/include/asm/agp.h b/arch/powerpc/include/asm/agp.=
h
index 416e12c..eb34fa5 100644
--- a/arch/powerpc/include/asm/agp.h
+++ b/arch/powerpc/include/asm/agp.h
@@ -2,9 +2,12 @@
#define _ASM_POWERPC_AGP_H
#ifdef __KERNEL__
=20
+#include <asm/cacheflush.h>
#include <asm/io.h>
=20
-#define map_page_into_agp(page)
+#define map_page_into_agp(page) \
+ flush_dcache_range((unsigned long)page_address(page), \
+ (unsigned long)page_address(page) + PAGE_SIZE)
#define unmap_page_from_agp(page)
#define flush_agp_cache() mb()
=20
--=20
Earthling Michel D=C3=A4nzer | http://www.amd.c=
om
Libre software enthusiast | Debian, X and DRI developer
next prev parent reply other threads:[~2012-04-18 10:44 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-17 19:49 PowerPC radeon KMS - is it possible? o jordan
2012-04-18 6:35 ` Michel Dänzer
2012-04-18 6:59 ` Benjamin Herrenschmidt
[not found] ` <1334732346.1159.5.camel__22339.9641145535$1334732429$gmane$org@pasglop>
2012-04-18 7:46 ` Andreas Schwab
2012-04-18 10:35 ` Benjamin Herrenschmidt
2012-04-18 10:37 ` Benjamin Herrenschmidt
2012-04-18 10:54 ` Michel Dänzer
2012-04-18 11:23 ` Benjamin Herrenschmidt
2012-04-18 13:07 ` Michel Dänzer
2012-04-18 22:25 ` Benjamin Herrenschmidt
[not found] ` <1334730915.5989.265.camel__41553.0639271767$1334731329$gmane$org@thor.local>
2012-04-18 7:42 ` Andreas Schwab
2012-04-18 7:52 ` Michel Dänzer
2012-04-18 11:25 ` Andreas Schwab
2012-04-18 13:02 ` Michel Dänzer
2012-04-18 13:22 ` Andreas Schwab
2012-04-18 13:25 ` Michel Dänzer
2012-04-18 13:47 ` Andreas Schwab
2012-04-18 7:54 ` Andreas Schwab
2012-04-18 8:02 ` Michel Dänzer
2012-04-18 10:20 ` Benjamin Herrenschmidt
2012-04-18 10:34 ` Michel Dänzer
2012-04-18 10:44 ` Michel Dänzer [this message]
2012-04-18 11:19 ` Benjamin Herrenschmidt
2012-04-18 13:08 ` Michel Dänzer
2012-04-18 12:49 ` Andreas Schwab
2012-04-18 11:17 ` Benjamin Herrenschmidt
2012-04-18 13:27 ` Michel Dänzer
2012-04-18 11:30 ` Andreas Schwab
2012-04-18 13:38 ` Michel Dänzer
2012-04-18 14:28 ` Andreas Schwab
2012-04-18 14:31 ` Michel Dänzer
2012-04-18 14:55 ` Andreas Schwab
2012-04-18 15:01 ` Michel Dänzer
2012-04-18 15:49 ` Gerhard Pircher
2012-04-18 16:06 ` Michel Dänzer
2012-04-18 16:23 ` Gerhard Pircher
2012-04-19 6:32 ` Michel Dänzer
2012-04-19 11:48 ` Gerhard Pircher
2012-04-19 12:41 ` Michel Dänzer
2012-04-18 15:39 ` Andreas Schwab
2012-04-20 11:15 Gerhard Pircher
2012-04-20 13:18 ` Michel Dänzer
2012-04-20 16:14 ` Gerhard Pircher
2012-04-23 9:56 ` Michel Dänzer
2012-04-23 16:45 ` Gerhard Pircher
2012-04-24 14:15 ` Michel Dänzer
2012-04-24 17:10 ` Gerhard Pircher
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=1334745854.5989.295.camel@thor.local \
--to=michel@daenzer.net \
--cc=benh@kernel.crashing.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=ojordan12345@hotmail.co.uk \
--cc=schwab@linux-m68k.org \
/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;
as well as URLs for NNTP newsgroup(s).