From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:34733 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753711Ab1H2OQr (ORCPT ); Mon, 29 Aug 2011 10:16:47 -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 16:17:12 +0200 Cc: linux-fbdev@vger.kernel.org, linux-media@vger.kernel.org, magnus.damm@gmail.com References: <1313746626-23845-1-git-send-email-laurent.pinchart@ideasonboard.com> <201108291534.35951.laurent.pinchart@ideasonboard.com> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201108291617.13236.laurent.pinchart@ideasonboard.com> Sender: linux-media-owner@vger.kernel.org List-ID: Hi Geert, 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 ? -- Regards, Laurent Pinchart From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Date: Mon, 29 Aug 2011 14:17:12 +0000 Subject: Re: [PATCH/RFC v2 1/3] fbdev: Add FOURCC-based format configuration API Message-Id: <201108291617.13236.laurent.pinchart@ideasonboard.com> List-Id: References: <1313746626-23845-1-git-send-email-laurent.pinchart@ideasonboard.com> <201108291534.35951.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 Hi Geert, 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 wi= th > >> > 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 ha= ve > > 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. Do you mean new ioctls to replace the FOURCC API proposal, or new ioctls fo= r=20 the above two operations ? --=20 Regards, Laurent Pinchart