From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH V7 11/12] Documentation: bridge: Add documentation for ps8622 DT properties Date: Tue, 23 Sep 2014 12:01:40 +0200 Message-ID: <20140923100139.GT30514@ulmo> References: <1409150399-12534-1-git-send-email-ajaykumar.rs@samsung.com> <5419760A.7020908@ti.com> <5419B52D.4060107@ti.com> <20140922080629.GC1470@ulmo> <542030DD.3060906@ti.com> <20140923060452.GD30514@ulmo> <5421201C.6000509@samsung.com> <20140923083514.GM30514@ulmo> <54214008.4040105@ti.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1938467845==" Return-path: In-Reply-To: <54214008.4040105@ti.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Tomi Valkeinen Cc: "devicetree@vger.kernel.org" , "linux-samsung-soc@vger.kernel.org" , Sean Paul , Daniel Vetter , sunil joshi , "dri-devel@lists.freedesktop.org" , Andrzej Hajda , Laurent Pinchart , Ajay kumar , Prashanth G , Ajay Kumar List-Id: devicetree@vger.kernel.org --===============1938467845== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="YqKeQn+qkMVHQmbT" Content-Disposition: inline --YqKeQn+qkMVHQmbT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 23, 2014 at 12:40:24PM +0300, Tomi Valkeinen wrote: > On 23/09/14 11:35, Thierry Reding wrote: >=20 > > Well, a display controller is never going to attach to a panel directly. >=20 > With parallel RGB, that (almost) happens. There's voltage level shifting > probably in the middle, but I don't see anything else there. The level shifting could be considered an encoder. Anyway, I didn't mean physically attach to a panel but rather in DRM. You'll always need an encoder and connector before you go to the panel. > > But I agree that it would be nice to unify bridges and encoders more. It > > should be possible to make encoder always a bridge (or perhaps even > > replace encoders with bridges altogether). Then once you're out of the > > DRM device everything would be a bridge until you get to a panel. >=20 > What exactly is a bridge and what is an encoder? Those are DRM > constructs, aren't they? Yes. I think bridges are mostly a superset of encoders. > As I see it, a video pipeline consist of a video source (display > controller usually), a chain of encoders (all of which may not be > strictly "encoders", they could be level shifters, muxes, ESD protection > devices or such), and either a display device like a panel or a > connector to outside world. Well, the panel itself is attached to a connector. The connector is really what userspace uses to control the output and indirectly the panel. > Am I right that in DRM world the encoder is the first device in the > display chain after the display controller, Yes. > and the next is a bridge? A bridge or a connector. Typically it would be a connector, but that's only if you don't have bridges in between. > That sounds totally artificial, and I hope we don't reflect that in the > DT side in any way. Yes, they are software concepts and I'm not aware of any of it being exposed in DT. A display controller is usually implemented as DRM CRTC object and outputs (DSI, eDP, HDMI) as encoder (often with a connector tied to it). Thierry --YqKeQn+qkMVHQmbT Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUIUUDAAoJEN0jrNd/PrOhF5AP/3xynALdWz1uhZONDGZz/jKW gfI8A4mfF62ftSnq7+5tzhW01gNj6m1nST2bsT2Yc7TopNenQF29afSMq9Mqvgm4 svGxgrMkNmv3JZhzlpEV6v9C4iXvAceu8C3597bGM3TxB0Xm7aZzQXBGm/czQbC9 uh8/dFi8/GevtVnmmW3da/mb311DVv+ya83O60lXkY//KQ8Gn8nXkNt8lesbDpcA BCet7Izh/thYHLnqt5d/fDG5Vz/8BBxkTcjZAByQgCl2vNbuA8HVkki3RAM2T5PU IhQW+tTG2GOYGca7SFweD5ZUXs2JNN44994YP/u6b8QRe2bB56GosQ5corxNJKR2 AMgOlM3Qg0lI/EGpjZIa/+C3mV1gqzPUTQsvGJeiRujwRIZiGHiSn6ObSXOy1Hgw 30qrHlIaIXVa7HP2BpDd5ItFg+p79BqhWrKRtNJV6KmF5wpsJEmMJyJSOKifuaCW KzeIkxmeUrwPyNAiRsqdTai6Igk3pATF53oTu5DZQ2WfZGcPqPT3WJBbkVhhadBL mEFGK4kllE/CPPtkC4PZMuh/YXTzEsIif1L94AKUs7lcldooaKKP2sFcsyF9Wkq/ rda4AI1xqHpsJefhyGzvDL2VuA0jDMpxDj/VGBQb7PS5ksltAlbnYXTzEW2xsbZA fmWL+egEh2WAqSc+8dZ/ =L3HE -----END PGP SIGNATURE----- --YqKeQn+qkMVHQmbT-- --===============1938467845== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel --===============1938467845==--