[Qemu-devel] VGA cirrus patch prevents video output

[Qemu-devel] VGA cirrus patch prevents video output

[Programmingkid]

I noticed that the video in QEMU stopped working. When I start qemu-system-ppc all I see is a black window. Not even OpenBIOS displays anything. After some bisecting I found out it was this patch that causes the problem: 

Commit 29f9cef39eb1ae55e82c6763eb22d7a1bdff7276
Author: Sebastian Bauer <mail@sebastianbauer.info>
Date:   Mon Jul 2 21:13:45 2018 +0200

    ppc: Include vga cirrus card into the compiling process
    
    Drivers for this card exists on PPC-based AmigaOS guests so it is useful to
    allow users to emulate the graphics card for PPC machines.
    
    As cirrus vga is currently preferred over std(vga) in absence of any user
    choice, this change also sets the default display of spapr machines to
    std as otherwise qemu refuses to start these machines. Not specifying an
    explicit graphics mode is for instance done by 'make check'.
    
    Signed-off-by: Sebastian Bauer <mail@sebastianbauer.info>
    Signed-off-by: David Gibson <david@gibson.dropbear.id.au>


I think a solution to this problem might be to have the mac99 machine use "-vga std" as default. When I use -vga std, video works again.

Re: [Qemu-devel] VGA cirrus patch prevents video output

[David Gibson]

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On Thu, Jul 05, 2018 at 10:41:43PM -0400, Programmingkid wrote:
> I noticed that the video in QEMU stopped working. When I start qemu-system-ppc all I see is a black window. Not even OpenBIOS displays anything. After some bisecting I found out it was this patch that causes the problem: 
> 
> Commit 29f9cef39eb1ae55e82c6763eb22d7a1bdff7276
> Author: Sebastian Bauer <mail@sebastianbauer.info>
> Date:   Mon Jul 2 21:13:45 2018 +0200
> 
>     ppc: Include vga cirrus card into the compiling process
>     
>     Drivers for this card exists on PPC-based AmigaOS guests so it is useful to
>     allow users to emulate the graphics card for PPC machines.
>     
>     As cirrus vga is currently preferred over std(vga) in absence of any user
>     choice, this change also sets the default display of spapr machines to
>     std as otherwise qemu refuses to start these machines. Not specifying an
>     explicit graphics mode is for instance done by 'make check'.
>     
>     Signed-off-by: Sebastian Bauer <mail@sebastianbauer.info>
>     Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> 
> 
> I think a solution to this problem might be to have the mac99
> machine use "-vga std" as default. When I use -vga std, video works
> again.

There are already patches in the works to fix this.


-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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