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Re: [Qemu-ppc] Bug in qemu-system-ppc in Windows using the SDL2 GUI
From: |
Mark Cave-Ayland |
Subject: |
Re: [Qemu-ppc] Bug in qemu-system-ppc in Windows using the SDL2 GUI |
Date: |
Fri, 24 Mar 2017 08:56:05 +0000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.6.0 |
On 24/03/17 08:47, Howard Spoelstra wrote:
> Hi,
>
> Running qemu-system-ppc.exe in windows with the SDL2 GUI results in a
> hangup. I bisected to this commit:
>
> 8bb93c6f99a42c2e0943bc904b283cd622d302c5 is the first bad commit
> commit 8bb93c6f99a42c2e0943bc904b283cd622d302c5
> Author: Alex Bennée <address@hidden>
> Date: Wed Mar 15 14:48:25 2017 +0000
>
> ui/console: ensure graphic updates don't race with TCG vCPUs
>
> Commit 8d04fb55..
>
> tcg: drop global lock during TCG code execution
>
> ..broke the assumption that updates to the GUI couldn't happen at the
> same time as TCG vCPUs where running. As a result the TCG vCPU could
> still be updating a directly mapped frame-buffer while the display
> side was updating. This would cause artefacts to appear when the
> update code assumed that memory block hadn't changed.
>
> The simplest solution is to ensure the two things can't happen at the
> same time like the old BQL locking scheme. Here we use the solution
> introduced for MTTCG and schedule the update as async_safe_work when
> we know no vCPUs can be running.
>
> Reported-by: Mark Cave-Ayland <address@hidden>
> Signed-off-by: Alex Bennée <address@hidden>
> Message-id: address@hidden
> Cc: BALATON Zoltan <address@hidden>
> Cc: Gerd Hoffmann <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> Signed-off-by: Alex Bennée <address@hidden>
>
> [ kraxel: updated comment clarifying the display adapters are buggy
> and this is a temporary workaround ]
>
> Signed-off-by: Gerd Hoffmann <address@hidden>
Hi Howard,
Alex posted another patch yesterday to resolve a similar issue:
https://lists.nongnu.org/archive/html/qemu-devel/2017-03/msg04474.html.
Does applying the above patch help at all?
ATB,
Mark.