Re: [Qemu-devel] [RfC PATCH 0/4] make display updates thread safe.

[Mark Cave-Ayland]

On 03/04/17 09:44, Gerd Hoffmann wrote:

>   Hi,
> 
>> I've spent a bit of time over the weekend attempting to convert the
>> SPARC CG3/TCX framebuffers over to use your new code and pushed the
>> result to my github branch here:
>> https://github.com/mcayland/qemu/commits/vga-fixes-sparc.
> 
> work/vga-fixes branch updated & rebased to latest master, with your
> patches added.

I've just rebased on your branch with some extra fixes which should be
squashed into the earlier commits and pushed to github again - see the
commit messages for more information.

>> 2) Redraw issues with CG3/TCX after conversion
>>
>> Despite the conversion from your patches looking reasonably
>> straightforward, I still see problems with areas of the screen not
>> updating after conversion. I can easily reproduce these locally as follows:
>>
>> ./qemu-system-sparc -vga cg3 -prom-env 'auto-boot?=false'
>> ./qemu-system-sparc -vga tcx -g 1024x768x8 -prom-env 'auto-boot?=false'
>> ./qemu-system-sparc -vga tcx -g 1024x768x24 -prom-env 'auto-boot?=false'
> 
> Hmm, I have a blank screen only (yellow with cg3, black with tcx).
> No openfirmware prompt showing up ...

Yeah it's slightly baffling. The easiest one to look at is cg3 since
it's a simple 8-bit palette dumb framebuffer with 256 colors, i.e. the
differences between 8d3af4a~1 and 8d3af4a ("cg3: make display updates
thread safe") in your updated branch. If nothing seems wrong with the
conversion (once my latest fixes have been squashed in) then I presume
something odd is happening in the dirty bitmap code...


ATB,

Mark.