From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752605AbbCJKqI (ORCPT ); Tue, 10 Mar 2015 06:46:08 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:38013 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751868AbbCJKqE (ORCPT ); Tue, 10 Mar 2015 06:46:04 -0400 Message-ID: <54FECB5D.1020908@ti.com> Date: Tue, 10 Mar 2015 12:45:49 +0200 From: Tomi Valkeinen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Maxime Ripard , =?windows-1252?Q?Thomas_Niederpr=FCm?= CC: , , Subject: Re: [PATCH 5/8] fbdev: ssd1307fb: Add module parameter bitsperpixel. References: <1423261694-5939-1-git-send-email-niederp@physik.uni-kl.de> <1423261694-5939-6-git-send-email-niederp@physik.uni-kl.de> <20150207112043.GO2079@lukather> <20150207170503.045490aa@maestro.intranet> <20150214155415.GC25269@lukather> In-Reply-To: <20150214155415.GC25269@lukather> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="8NO6pTL33IeoXnGo4GfPvXRQQotUmMtMn" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --8NO6pTL33IeoXnGo4GfPvXRQQotUmMtMn Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 14/02/15 17:54, Maxime Ripard wrote: > On Sat, Feb 07, 2015 at 05:05:03PM +0100, Thomas Niederpr=FCm wrote: >> Am Sat, 7 Feb 2015 12:20:43 +0100 >> schrieb Maxime Ripard : >> >>> On Fri, Feb 06, 2015 at 11:28:11PM +0100, niederp@physik.uni-kl.de >>> wrote: >>>> From: Thomas Niederpr=FCm >>>> >>>> This patch adds a module parameter 'bitsperpixel' to adjust the >>>> colordepth of the framebuffer. All values >1 will result in memory >>>> map of the requested color depth. However only the MSB of each >>>> pixel will be sent to the device. The framebuffer identifies itself >>>> as a grayscale display with the specified depth. >>> >>> I'm not sure this is the right thing to do. >>> >>> The bits per pixel for this display is rightfully defined, used and >>> reported to the userspace, why would you want to change that? >> >> You are right of course. The display is 1bpp and it reports to be 1 >> bpp. The problem is that there is almost no userspace library that can= >> handle 1 bit framebuffers correctly. So it is nice if the framebuffer >> (optionally) can expose itself as 8 bits per pixel grayscale to the >> userspace program. As an example this allows to run DirectFB on the >> framebuffer, which is not possible out of the box for 1bpp. >> >> Also note that if do not set the module parameter at load time >> the framebuffer will be 1bpp. So you have to actively set that module >> parameter to make the framebuffer pretend to be more than 1bpp. >> >> In any case I don't cling to that patch, I just thought it was a nice >> feature. >=20 > I'd say that the right fix would be to patch DirectFB, instead of > faking that in the kernel. >=20 > But again, that's probably Tomi's call, not mine. Right, I'm not thrilled =3D). I don't think it's a good idea to lie to th= e userspace (except when fixing regressions). Tomi --8NO6pTL33IeoXnGo4GfPvXRQQotUmMtMn Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJU/stdAAoJEPo9qoy8lh71FKQQAKYv5frUA9ZKCQSBJd3digNv MGA7tZFjit73tfD4PC3ozZCZOqAu2HeLPkq8wdEU23v+UooeC50b4g820b2AKeEM uTWKS3wxb1QWKCw7coLcp173bDGCpleu8AOcFyC5L6wkiShTJHcqZxiBLjJorIci 4Go5hxdOO73Psxw4TfxzG6Dp73wlzRs47Dvm4zZIrbPMlupX9mB/UDBgckbaAjZq nu0cr4aw9qk3keZFWfeSuiJHKZixWxarhBFIK1SCv4N5TIilbF5ELT2eliu+GfD4 mXsiVvxKNIwnm7bLJzu02MfrPmf1bqrydCxwidIGHoFApGbfZ0RaA/mOGoOKYaZx BWlC09IITzWLbVsyL6trwJD/JmOMoMCyfOgC76KkI9dmn7448l12OU36s5wF8fsL l/E2ra3dj41OwEyOzV7oOzUHLzQNLrjn2PSMrqpf/TV/eQ1/v+jFk2sIM/kVesei pp7Rj/ZvHwRSgr0ojuTcjwSMhIoA4YHJqkxr4DfNuF+ktikCG1IXPtTDIh1hKH+r E8TJJNPRH36O1tW/NZq/g75Mk7DtgkWeokDXmeerMGywJUNFsg7ynflIZ5HGMalO /s7TLA/eSO1N8fKfRTnqd7r1R4zojCq0VGEkD6le9eqQOTRQZICTfyMlvzNd2Ynv b5gV5QZYGWNeHdbz3R2X =1Yl7 -----END PGP SIGNATURE----- --8NO6pTL33IeoXnGo4GfPvXRQQotUmMtMn--