[Qemu-devel] PXA2xx LCD vs. dedicated framebuffer

[Qemu-devel] PXA2xx LCD vs. dedicated framebuffer

[Thierry Reding]

I'm working on adding support to QEMU for some of the boards that the company
I work for develops. The boards have a PXA270 and an FPGA to implement
additional functionality, such as a dedicated graphics controller. The
problem I'm facing now is that whenever the dedicated graphics controller is
initialized in QEMU it registers as a secondary DisplayState because the
PXA2xx LCD is already present.

Is there a way to make QEMU ignore the PXA2xx LCD or prefer the dedicated
controller as primary DisplayState? The only way I could find was to comment
out the PXA2xx LCD initialization or patch the sources to disable the LCD
using a flag during PXA2xx setup.

Thierry

Re: [Qemu-devel] PXA2xx LCD vs. dedicated framebuffer

[Filip Navara]

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On Fri, Jun 19, 2009 at 12:04 PM, Thierry Reding <
thierry.reding@avionic-design.de> wrote:

> I'm working on adding support to QEMU for some of the boards that the
> company
> I work for develops. The boards have a PXA270 and an FPGA to implement
> additional functionality, such as a dedicated graphics controller. The
> problem I'm facing now is that whenever the dedicated graphics controller
> is
> initialized in QEMU it registers as a secondary DisplayState because the
> PXA2xx LCD is already present.
>
> Is there a way to make QEMU ignore the PXA2xx LCD or prefer the dedicated
> controller as primary DisplayState? The only way I could find was to
> comment
> out the PXA2xx LCD initialization or patch the sources to disable the LCD
> using a flag during PXA2xx setup.
>
> Thierry


As far as I know there's currently no way to achieve it except for
commenting out the code or changing the order of initialization. Note that
once the "devtree" patch is merged and the PXA2xx code is migrated to it
then it will be possible to create a machine description that will not
contain the LCD controller. Such machine description doesn't require
recompiling of whole QEMU to use it.

Best regards,
Filip Navara

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Re: [Qemu-devel] PXA2xx LCD vs. dedicated framebuffer

[Thierry Reding]

* Filip Navara wrote:
> On Fri, Jun 19, 2009 at 12:04 PM, Thierry Reding <
> thierry.reding@avionic-design.de> wrote:
> 
> > I'm working on adding support to QEMU for some of the boards that the
> > company
> > I work for develops. The boards have a PXA270 and an FPGA to implement
> > additional functionality, such as a dedicated graphics controller. The
> > problem I'm facing now is that whenever the dedicated graphics controller
> > is
> > initialized in QEMU it registers as a secondary DisplayState because the
> > PXA2xx LCD is already present.
> >
> > Is there a way to make QEMU ignore the PXA2xx LCD or prefer the dedicated
> > controller as primary DisplayState? The only way I could find was to
> > comment
> > out the PXA2xx LCD initialization or patch the sources to disable the LCD
> > using a flag during PXA2xx setup.
> >
> > Thierry
> 
> 
> As far as I know there's currently no way to achieve it except for
> commenting out the code or changing the order of initialization. Note that
> once the "devtree" patch is merged and the PXA2xx code is migrated to it
> then it will be possible to create a machine description that will not
> contain the LCD controller. Such machine description doesn't require
> recompiling of whole QEMU to use it.
> 
> Best regards,
> Filip Navara

Great! I guess I can wait and work around the problem in the meantime by
commenting out the code. Thanks.

Thierry