Hi Laurent,
On Mon, Aug 29, 2011 at 16:17, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> 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.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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