From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:59302 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753237Ab1H2OOj convert rfc822-to-8bit (ORCPT ); Mon, 29 Aug 2011 10:14:39 -0400 MIME-Version: 1.0 In-Reply-To: <201108291534.35951.laurent.pinchart@ideasonboard.com> References: <1313746626-23845-1-git-send-email-laurent.pinchart@ideasonboard.com> <201108291455.36145.laurent.pinchart@ideasonboard.com> <201108291534.35951.laurent.pinchart@ideasonboard.com> Date: Mon, 29 Aug 2011 16:14:38 +0200 Message-ID: Subject: Re: [PATCH/RFC v2 1/3] fbdev: Add FOURCC-based format configuration API From: Geert Uytterhoeven To: Laurent Pinchart Cc: linux-fbdev@vger.kernel.org, linux-media@vger.kernel.org, magnus.damm@gmail.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-media-owner@vger.kernel.org List-ID: Hi Laurent, 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. Gr{oetje,eeting}s,                         Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Date: Mon, 29 Aug 2011 14:14:38 +0000 Subject: Re: [PATCH/RFC v2 1/3] fbdev: Add FOURCC-based format configuration API Message-Id: List-Id: References: <1313746626-23845-1-git-send-email-laurent.pinchart@ideasonboard.com> <201108291455.36145.laurent.pinchart@ideasonboard.com> <201108291534.35951.laurent.pinchart@ideasonboard.com> In-Reply-To: <201108291534.35951.laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Laurent Pinchart Cc: linux-fbdev@vger.kernel.org, linux-media@vger.kernel.org, magnus.damm@gmail.com Hi Laurent, 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? >> >> =C2=A0 - When using a mode that cannot be represented in the legacy w= ay, >> > >> > Definitely. >> > >> >> =C2=A0 - But what with modes that can be represented? Legacy software= cannot >> >> =C2=A0 =C2=A0 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: >> =C2=A0 - The video mode is configured using a FOURCC-aware tool ("fbset = on >> steroids"). > > Such as http://git.ideasonboard.org/?p=FBdev-test.git;a=3Dsummary :-) Yep. >> =C2=A0 =C2=A0 Later the user runs a legacy application. >> =C2=A0 =C2=A0 =C2=A0 =3D> 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. > >> =C2=A0 - 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, =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k= .org 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 t= hat. =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0=C2=A0 -- Linus Torvalds