Hi Geert,
On Monday 29 August 2011 16:14:38 Geert Uytterhoeven wrote:
> On Mon, Aug 29, 2011 at 15:34, Laurent Pinchart wrote:
> > On Monday 29 August 2011 15:09:04 Geert Uytterhoeven wrote:
> >> On Mon, Aug 29, 2011 at 14:55, Laurent Pinchart wrote:
> >> >> When will the driver report FB_{TYPE,VISUAL}_FOURCC?
> >> >> - When using a mode that cannot be represented in the legacy way,
> >> >
> >> > Definitely.
> >> >
> >> >> - But what with modes that can be represented? Legacy software
> >> >> cannot handle FB_{TYPE,VISUAL}_FOURCC.
> >> >
> >> > My idea was to use FB_{TYPE,VISUAL}_FOURCC only when the mode is
> >> > configured using the FOURCC API. If FBIOPUT_VSCREENINFO is called with
> >> > a non-FOURCC format, the driver will report non-FOURCC types and
> >> > visuals.
> >>
> >> Hmm, two use cases:
> >> - The video mode is configured using a FOURCC-aware tool ("fbset on
> >> steroids").
> >
> > Such as http://git.ideasonboard.org/?p=fbdev-test.git;a=summary :-)
>
> Yep.
>
> >> Later the user runs a legacy application.
> >> => Do not retain FOURCC across opening of /dev/fb*.
> >
> > I know about that problem, but it's not that easy to work around. We have
> > no per-open fixed and variable screen info, and FB devices can be opened
> > by multiple applications at the same time.
> >
> >> - Is there an easy way to force FOURCC reporting, so new apps don't
> >> have to support parsing the legacy formats? This is useful for new apps
> >> that want to support (a subset of) FOURCC modes only.
> >
> > Not at the moment.
>
> So perhaps we do need new ioctls instead...
> That would also ease an in-kernel translation layer.
Do you mean new ioctls to replace the FOURCC API proposal, or new ioctls for
the above two operations ?
--
Regards,
Laurent Pinchart
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