From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936420Ab0COOAH (ORCPT ); Mon, 15 Mar 2010 10:00:07 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:57225 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936360Ab0COOAE (ORCPT ); Mon, 15 Mar 2010 10:00:04 -0400 Date: Mon, 15 Mar 2010 14:59:45 +0100 From: Luotao Fu To: Russell King - ARM Linux Cc: Luotao Fu , Andrew Morton , Andres Salomon , Alessandro Rubini , Krzysztof Helt , Kevin Wells , linux-kernel@vger.kernel.org Subject: Re: [PATCH] amba-clcd: add RGB444 support Message-ID: <20100315135945.GA4584@pengutronix.de> Mail-Followup-To: Russell King - ARM Linux , Luotao Fu , Andrew Morton , Andres Salomon , Alessandro Rubini , Krzysztof Helt , Kevin Wells , linux-kernel@vger.kernel.org References: <1268659809-3609-1-git-send-email-l.fu@pengutronix.de> <20100315133810.GE700@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ZGiS0Q5IWpPtfppv" Content-Disposition: inline In-Reply-To: <20100315133810.GE700@n2100.arm.linux.org.uk> X-PGP-Key-ID: 0xE5325261 X-URL: http://www.pengutronix.de/ X-Sent-From: Pengutronix Entwicklungszentrum Nord - Hildesheim X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Impressum: Pengutronix - Industrial Linux Solutions Handelsregister: Amtsgericht Hildesheim, HRA 2686 Peiner Strasse 6-8, 31137 Hildesheim, Germany Phone: +49-5121-206917-0 | Fax: +49-5121-206917-5555 Inhaber: Dipl.-Ing. Robert Schwebel X-Message-Flag: See Message Headers for Impressum X-Uptime: 14:46:00 up 6:27, 2 users, load average: 0.00, 0.03, 0.00 User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:250:baff:feac:3723 X-SA-Exim-Mail-From: l.fu@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --ZGiS0Q5IWpPtfppv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Russell, On Mon, Mar 15, 2010 at 01:38:10PM +0000, Russell King - ARM Linux wrote: > On Mon, Mar 15, 2010 at 02:30:09PM +0100, Luotao Fu wrote: > > This one adds RGB444 (bpp=3D12) support to amba clcd drivers. Tested on= a lpc3250 > > based platform. >=20 > No - this is wrong. You have a 16bpp display. bpp is the number of bits > in the framebuffer between two successive pixels. It is not the number of > bits used for the pixel information. >=20 > The only case where you have a 12bpp display is if you have two pixels > packed into three bytes. > For 12bpp actually 16bits/pixel is used. I'm aware of that. That's the reason why the fb.var.bits_per_pixel is set to 16 in clcdfb_decode if it is originally set to 12 from the platform file to make usage of 16bpp display. omapfb driver does quite the same. On my framebuffer controller (here on a lpc3250) there is hardware RGB444 support. Switching to this mode will spare some pins. What I intend to do with this patch is to make use of this feature. Similar RGB444 Support can be found in omapfb. cheers Luotao Fu --=20 Pengutronix e.K. | Dipl.-Ing. Luotao Fu | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | --ZGiS0Q5IWpPtfppv Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkuePVEACgkQkLuxfMCkDTYxAgCfU/uIrzq1Cap4QD9jqONGTeNN dMMAn1cn8ahp2prpftIhfU/SGFXCv/DN =kHC2 -----END PGP SIGNATURE----- --ZGiS0Q5IWpPtfppv--