Hi Geert,
On Monday 29 August 2011 16:26:02 Geert Uytterhoeven wrote:
> On Mon, Aug 29, 2011 at 16:17, Laurent Pinchart wrote:
> > 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 ?
>
> New ioctls to replace the FOURCC proposal.
*sigh*...
I'd like other people's opinion on this before throwing everything away.
Florian, Magnus, Guennadi, others, what do you think ?
--
Regards,
Laurent Pinchart
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