From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: Re: Attempt to start X-Server at Xen 3.5 Dom0 (
	2.6.31) on top of Ubuntu 9.04 Server
Date: Thu, 24 Sep 2009 12:48:39 -0400
Message-ID: <20090924164839.GA608@phenom.dumpdata.com>
References: <838120.79569.qm@web56105.mail.re3.yahoo.com>
	<454367.84289.qm@web56101.mail.re3.yahoo.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: quoted-printable
Return-path: <xen-devel-bounces@lists.xensource.com>
Content-Disposition: inline
In-Reply-To: <454367.84289.qm@web56101.mail.re3.yahoo.com>
List-Unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Boris Derzhavets <bderzhavets@yahoo.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>, Xen-devel <xen-devel@lists.xensource.com>
List-Id: xen-devel@lists.xenproject.org

On Wed, Sep 23, 2009 at 10:54:09PM -0700, Boris Derzhavets wrote:
> Sorry , there is difference in dmesg reports under xen and as vanilla.
>=20
> dmesg under xen:-
>=20
> [=A0 243.858191] mtrr: type mismatch for d0000000,10000000 old: write-b=
ack new: write-combining
> [=A0 243.858263] mtrr: type mismatch for d0000000,10000000 old: write-b=
ack new: write-combining
> [=A0 244.132051] mtrr: type mismatch for d0000000,10000000 old: write-b=
ack new: write-combining
> [=A0 244.132115] mtrr: type mismatch for d0000000,10000000 old: write-b=
ack new: write-combining
> [=A0 244.132181] mtrr: type mismatch for d0000000,10000000 old: write-b=
ack new: write-combining
> [=A0 244.157265] [drm] Setting GART location based on new memory map
> [=A0 244.190885] [drm] Loading RV730/RV740 PFP Microcode
> [=A0 244.190911] [drm] Loading RV730/RV740 CP Microcode
> [=A0 244.205974] [drm] Resetting GPU
> ->=A0=A0=A0 [=A0 244.310103] [drm] writeback test failed
> [=A0 251.220092] [drm] Resetting GPU
>=20
> dmesg 2.6.31 vanilla:-
>=20
> [=A0=A0 36.941430] [drm] Initialized drm 1.1.0 20060810
> [=A0=A0 36.988225] pci 0000:01:00.0: setting latency timer to 64
> [=A0=A0 36.988341] [drm] Initialized radeon 1.31.0 20080528 for 0000:01=
:00.0 on minor 0
> [=A0=A0 36.989222] mtrr: type mismatch for d0000000,10000000 old: write=
-back new: write-combining
> [=A0=A0 37.210900] mtrr: type mismatch for d0000000,10000000 old: write=
-back new: write-combining
> [=A0=A0 37.210940] mtrr: type mismatch for d0000000,10000000 old: write=
-back new: write-combining
> [=A0=A0 37.210976] mtrr: type mismatch for d0000000,10000000 old: write=
-back new: write-combining
> [=A0=A0 37.232744] [drm] Setting GART location based on new memory map
> [=A0=A0 37.248205] [drm] Loading RV730/RV740 PFP Microcode
> [=A0=A0 37.248227] [drm] Loading RV730/RV740 CP Microcode
> [=A0=A0 37.263281] [drm] Resetting GPU
> -> [=A0=A0 37.263336] [drm] writeback test succeeded in 1 usecs

I think I know why this is not working.

The DRM and its AGP modules call virt_to_gart and gart_to_virt, which is =
defined as:

#define virt_to_gart(x) (phys_to_gart(virt_to_phys(x)))
#define gart_to_virt(x) (phys_to_virt(gart_to_phys(x)))
and phys_to_gart and gart_to_phys are:
#define phys_to_gart(x) swiotlb_phys_to_bus(NULL, (x))
#define gart_to_phys(x) swiotlb_bus_to_phys(NULL, (x))

The swiotlb_* calls do return the wrong information when the
kernel is running under Xen.