From: Anthony Liguori <anthony@codemonkey.ws>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] CONFIG_FB_CIRRUS for Linux guests
Date: Tue, 26 Jan 2010 10:54:17 -0600 [thread overview]
Message-ID: <4B5F1E39.1000909@codemonkey.ws> (raw)
In-Reply-To: <4B5EFFBC.8020703@siemens.com>
On 01/26/2010 08:44 AM, Jan Kiszka wrote:
> Hi,
>
> just received some Linux guest kernel that refuses to properly use its
> framebuffer console under QEMU (probably any version, tried down to some
> 0.10.x). It turned out that it has CONFIG_FB_CIRRUS enabled and fails to
> initialize the display when this is actually used. Anyone came across
> this before or has some idea what goes wrong?
>
Looks like it worked at some point:
commit ca896ef389fc44c7a673d1bd2b94823e28da37a1
Author: aurel32 <aurel32@c046a42c-6fe2-441c-8c8c-71466251a162>
Date: Thu May 8 12:21:27 2008 +0000
cirrusfb: proper "Attribute Controller Toggle Readback" register
behaviour
(Marcelo Tosatti)
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4386
c046a42c-6fe2-441c
The cirrusfb Linux driver uses the toggle readback register to determine
whether to flip 0xC30 to data/address mode.
Without proper implementation the VGA mode will be erroneously set to
blank resulting in crashes when starting BITBLT.
3d4h index 24h (R): Attribute Controller Toggle Readback Register
bit 7 If set the Attribute Controller will next access a data register, if
clear it'll access the index register
Signed-off-by: Marcelo Tosatti<mtosatti@redhat.com>
Regards,
Anthony Liguori
> Jan
>
>
next prev parent reply other threads:[~2010-01-26 16:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-26 14:44 [Qemu-devel] CONFIG_FB_CIRRUS for Linux guests Jan Kiszka
2010-01-26 16:02 ` Alexander Graf
2010-01-26 18:01 ` René Rebe
2010-01-26 16:54 ` Anthony Liguori [this message]
2010-01-26 18:09 ` Jan Kiszka
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