Hi Laurent,
On Mon, Aug 29, 2011 at 15:34, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> 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.
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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