From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:52778 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753646Ab1H2Obk (ORCPT ); Mon, 29 Aug 2011 10:31:40 -0400 From: Laurent Pinchart To: Geert Uytterhoeven Subject: Re: [PATCH/RFC v2 1/3] fbdev: Add FOURCC-based format configuration API Date: Mon, 29 Aug 2011 16:32:06 +0200 Cc: linux-fbdev@vger.kernel.org, linux-media@vger.kernel.org, magnus.damm@gmail.com, Florian Tobias Schandinat , Guennadi Liakhovetski References: <1313746626-23845-1-git-send-email-laurent.pinchart@ideasonboard.com> <201108291617.13236.laurent.pinchart@ideasonboard.com> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201108291632.06717.laurent.pinchart@ideasonboard.com> Sender: linux-media-owner@vger.kernel.org List-ID: 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Date: Mon, 29 Aug 2011 14:32:06 +0000 Subject: Re: [PATCH/RFC v2 1/3] fbdev: Add FOURCC-based format configuration API Message-Id: <201108291632.06717.laurent.pinchart@ideasonboard.com> List-Id: References: <1313746626-23845-1-git-send-email-laurent.pinchart@ideasonboard.com> <201108291617.13236.laurent.pinchart@ideasonboard.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Geert Uytterhoeven Cc: linux-fbdev@vger.kernel.org, linux-media@vger.kernel.org, magnus.damm@gmail.com, Florian Tobias Schandinat , Guennadi Liakhovetski 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, > >> >> >=20 > >> >> > Definitely. > >> >> >=20 > >> >> >> - But what with modes that can be represented? Legacy software > >> >> >> cannot handle FB_{TYPE,VISUAL}_FOURCC. > >> >> >=20 > >> >> > 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. > >> >>=20 > >> >> Hmm, two use cases: > >> >> - The video mode is configured using a FOURCC-aware tool ("fbset = on > >> >> steroids"). > >> >=20 > >> > Such as http://git.ideasonboard.org/?p=FBdev-test.git;a=3Dsummary :-) > >>=20 > >> Yep. > >>=20 > >> >> Later the user runs a legacy application. > >> >> =3D> Do not retain FOURCC across opening of /dev/fb*. > >> >=20 > >> > 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. > >> >=20 > >> >> - 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. > >> >=20 > >> > Not at the moment. > >>=20 > >> So perhaps we do need new ioctls instead... > >> That would also ease an in-kernel translation layer. > >=20 > > Do you mean new ioctls to replace the FOURCC API proposal, or new ioctls > > for the above two operations ? >=20 > New ioctls to replace the FOURCC proposal. *sigh*... I'd like other people's opinion on this before throwing everything away.=20 Florian, Magnus, Guennadi, others, what do you think ? --=20 Regards, Laurent Pinchart