From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F30FC433B4 for ; Mon, 26 Apr 2021 12:22:26 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AF64661040 for ; Mon, 26 Apr 2021 12:22:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF64661040 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 09FAD88310; Mon, 26 Apr 2021 12:22:25 +0000 (UTC) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 15BA3892A1 for ; Mon, 26 Apr 2021 12:22:23 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 9DA0CAC38; Mon, 26 Apr 2021 12:22:21 +0000 (UTC) Subject: Re: [PATCH v4 0/9] drm: Support simple-framebuffer devices and firmware fbs To: Geert Uytterhoeven , Gerd Hoffmann References: <20210416090048.11492-1-tzimmermann@suse.de> <20210420092204.7azdb7nxgofegjht@sirius.home.kraxel.org> From: Thomas Zimmermann Message-ID: Date: Mon, 26 Apr 2021 14:22:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: bluescreen_avenger@verizon.net, "open list:DOCUMENTATION" , David Airlie , Greg KH , Jonathan Corbet , Emil Velikov , Liam Girdwood , DRI Development , virtualization@lists.linux-foundation.org, Hans de Goede , Mark Brown , Sam Ravnborg Content-Type: multipart/mixed; boundary="===============0786361624==" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --===============0786361624== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="j3vG4wKnJAormeO5lVRoEdvWqXNHNlWdV" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --j3vG4wKnJAormeO5lVRoEdvWqXNHNlWdV Content-Type: multipart/mixed; boundary="2FNIcz9YNwfBpAUZWENkhSI2HLlwytP1d"; protected-headers="v1" From: Thomas Zimmermann To: Geert Uytterhoeven , Gerd Hoffmann Cc: bluescreen_avenger@verizon.net, Jonathan Corbet , David Airlie , Emil Velikov , "open list:DOCUMENTATION" , Liam Girdwood , virtualization@lists.linux-foundation.org, Hans de Goede , Mark Brown , DRI Development , Greg KH , Sam Ravnborg Message-ID: Subject: Re: [PATCH v4 0/9] drm: Support simple-framebuffer devices and firmware fbs References: <20210416090048.11492-1-tzimmermann@suse.de> <20210420092204.7azdb7nxgofegjht@sirius.home.kraxel.org> In-Reply-To: --2FNIcz9YNwfBpAUZWENkhSI2HLlwytP1d Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Hi Am 20.04.21 um 11:27 schrieb Geert Uytterhoeven: > Hi Gerd, >=20 > On Tue, Apr 20, 2021 at 11:22 AM Gerd Hoffmann wrot= e: >>>>> Patches 4 to 8 add the simpledrm driver. It's build on simple DRM h= elpers >>>>> and SHMEM. It supports 16-bit, 24-bit and 32-bit RGB framebuffers. = During >>>> >>>> .... if support for 8-bit frame buffers would be added? >>> >>> Is that 8-bit greyscale or 8-bit indexed with 256 entry palette? Form= er >>> shouldn't be a big thing, but the latter is only really supported by = the >>> overall drm ecosystem in theory. Most userspace assumes that xrgb8888= >>> works, and we keep that illusion up by emulating it in kernel for hw = which >>> just doesn't support it. But reformatting xrgb8888 to c8 is tricky at= >>> best. >> >> Well. cirrus converts xrgb8888 on the fly to rgb888 or rgb565 >> (depending on display resolution). We could pull off the same trick >> here and convert to rgb332 (assuming we can program the palette with t= he >> color cube needed for that). Wouldn't look pretty, but would probably= >> work better than expecting userspace know what color palettes are in >> 2021 ... >=20 > Yeah, I already had a similar idea for Amiga HAM ;-) I vaguely remember that HAM mode uses some crazy format where pixel=20 colors depend in the values of their neighbors. (?) How complicated is=20 it to write a conversion from RGB to HAM? Best regards Thomas >=20 > Gr{oetje,eeting}s, >=20 > Geert >=20 --=20 Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany (HRB 36809, AG N=C3=BCrnberg) Gesch=C3=A4ftsf=C3=BChrer: Felix Imend=C3=B6rffer --2FNIcz9YNwfBpAUZWENkhSI2HLlwytP1d-- --j3vG4wKnJAormeO5lVRoEdvWqXNHNlWdV Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- wsF5BAABCAAjFiEExndm/fpuMUdwYFFolh/E3EQov+AFAmCGsHwFAwAAAAAACgkQlh/E3EQov+DV lg//T7tmFsNA85Ryaq43kUbOtlqmcj7ZRZmIOn53tHJll440AxyiFwERA/g6ZHEo44WKCQ6Y7R8j 8miZfCpgssWp00gkkROFaFhhEd8370QuTGOlFPe8R655rcdQYzsm8z5teGkdba0li3ONM8CdQVVH 6UGMuBbZvySDYuRtT1vqW/9AvOMbWn1ge1zJYp+VKH7tJKLQVLEd1gxgwC7EHxp11lPrL0G0IWOH lSUuXUFA80atM/0udglvjPdKeoDpVyYE9jAWzGSO5B/nsBmpmnQV1Id71D+u1bYkze/YIBxGT+gs WYUaPDKtmpZtUJh4GBlXsggdw5TviUZj+0MDY8iu9G5ihCvkl7hOsK+ZwMXa7KnrlFrizoCBDpaP BkPhW4/7iqS8lFs00ICiCJIW8wmK7aPM1jm6tWBetn2B7Um0UM34ndM9S/gO9LeRHpP+7DVaAZIV cezd6kRUbldR3KM1VKIvVoYxI55TkKQI5L8sMgMfDZx/z7OD8wbsgG97VSDwHI/lxN12pwWRbDDN l+p6gJZrLTqwft6gQHlVNqDLULZE5vGs01RYC1L99HNvgvja5U1hb6Uroo4O1Nj2BjfYiFLhUcg1 4FkQR8/SaUVXDC70YVIa9o6Jq1rzqm5bOLlv8+mpFx9HYE7Kh4yxlwjSp+B5+C0/WcaE0YyIdciz 8pw= =CgI8 -----END PGP SIGNATURE----- --j3vG4wKnJAormeO5lVRoEdvWqXNHNlWdV-- --===============0786361624== 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 https://lists.freedesktop.org/mailman/listinfo/dri-devel --===============0786361624==--