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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 25ABBC71155 for ; Wed, 2 Dec 2020 08:02:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1FAC20C56 for ; Wed, 2 Dec 2020 08:02:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728879AbgLBICl (ORCPT ); Wed, 2 Dec 2020 03:02:41 -0500 Received: from mx2.suse.de ([195.135.220.15]:53128 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726493AbgLBICl (ORCPT ); Wed, 2 Dec 2020 03:02:41 -0500 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 53EA6ABD2; Wed, 2 Dec 2020 08:01:59 +0000 (UTC) Subject: Re: [PATCH] fbdev: Remove udlfb driver From: Thomas Zimmermann To: Mikulas Patocka Cc: Daniel Vetter , linux-fbdev@vger.kernel.org, geert+renesas@glider.be, corbet@lwn.net, daniel.vetter@ffwll.ch, linux-doc@vger.kernel.org, bernie@plugable.com, dri-devel@lists.freedesktop.org, sam@ravnborg.org References: <20201130125200.10416-1-tzimmermann@suse.de> <20201130154147.GT401619@phenom.ffwll.local> <9e7cad29-a9c0-2e02-04a9-3149d7e15838@suse.de> Message-ID: Date: Wed, 2 Dec 2020 09:01:58 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <9e7cad29-a9c0-2e02-04a9-3149d7e15838@suse.de> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="4QEmHYAmn97ipMvLKAVzidpTp0CzotVig" Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --4QEmHYAmn97ipMvLKAVzidpTp0CzotVig Content-Type: multipart/mixed; boundary="g2nXcqKmfiVdxBUkyf25Q6uypK25c8Smd"; protected-headers="v1" From: Thomas Zimmermann To: Mikulas Patocka Cc: Daniel Vetter , linux-fbdev@vger.kernel.org, geert+renesas@glider.be, corbet@lwn.net, daniel.vetter@ffwll.ch, linux-doc@vger.kernel.org, bernie@plugable.com, dri-devel@lists.freedesktop.org, sam@ravnborg.org Message-ID: Subject: Re: [PATCH] fbdev: Remove udlfb driver References: <20201130125200.10416-1-tzimmermann@suse.de> <20201130154147.GT401619@phenom.ffwll.local> <9e7cad29-a9c0-2e02-04a9-3149d7e15838@suse.de> In-Reply-To: <9e7cad29-a9c0-2e02-04a9-3149d7e15838@suse.de> --g2nXcqKmfiVdxBUkyf25Q6uypK25c8Smd Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Am 02.12.20 um 08:55 schrieb Thomas Zimmermann: > Hi >=20 > Am 01.12.20 um 12:20 schrieb Mikulas Patocka: >> >> >> On Tue, 1 Dec 2020, Thomas Zimmermann wrote: >> >>> Hi >>> >>> Am 30.11.20 um 19:39 schrieb Mikulas Patocka: >>>> >>>> >>>> On Mon, 30 Nov 2020, Daniel Vetter wrote: >>>> >>>>> On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote: >>>>>> >>>>>> The framebuffer driver supports programs running full-screen=20 >>>>>> directly on >>>>>> the framebuffer console, such as web browser "links -g", image vie= wer >>>>>> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sd= l", >>>>>> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.= >>>>> >>>>> Hm this should in general work on drm drivers. Without that it's=20 >>>>> clear the >>>>> switch-over isn't really ready yet. >>>> >>>> I fixed it with this patch two years ago: >>>> https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.ht= ml >>>> >>>> But the patch never went through and the fb_defio feature was=20 >>>> removed in >>>> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa). >>>> >>>> >>>> Without fb_defio, the only other possibility how to update the=20 >>>> screen is >>>> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master=20 >>>> mode, so >>>> user programs like "links -g" can't issue it. >>> >>> That's confusing. DIRTYFB is only for DRM. >> >> Yes, you're right. >> >>> And why can links not run as DRM master mode? If it renders to the=20 >>> terminal, >>> it should act like a composer. In that case it almost certainly wants= =20 >>> master >>> status. >>> >>> Best regards >>> Thomas >> >> How can a userspace program acquire master mode without being suid? >=20 > For my understanding, there's no easy solution to that. :/ >=20 > I guess we (DRM devs) have to treat fbdev as the solution for use cases= =20 > such as ours. s/ours/yours >=20 > For the unplug issue, I'll try to reproduce and fix it. >=20 > For the performance problems, we might be able to squeeze a few more=20 > cycles out of it. >=20 > Best regards > Thomas >=20 >> >> Is there some "Hello World!" program that shows how to use DRM? I'm=20 >> not an >> expert in DRM, but if there were some tutorial+documentation, I could >> consider porting "links" to it. >> >> Mikulas >> >=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 --g2nXcqKmfiVdxBUkyf25Q6uypK25c8Smd-- --4QEmHYAmn97ipMvLKAVzidpTp0CzotVig 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+AFAl/HSfYFAwAAAAAACgkQlh/E3EQov+A4 pA/9GS90vDzxsEuokb7l3rmAoNSPBWVxht2CUEgFRopOrQZZOh2rB6tgE32ODTnwpXTsvw+b4ABb X3Nt0YCUAecSvDo0Vb2Tvf+dgidnT2HPtc8G6Lq7Y+QgYJTYmBq/xAxjbqjHoBLqMf2VBxCETyDl ARepztWJkNE1ZIa2nkwIQdJZPid4GU99BXVT/eRUZyY5L9gtMPdYNe0mmyHm1JSgjgTf58gN6Pae RCFK2lLY0rPmQH0vXj7Ery1kJFnB+/jBjSvVdJXhoqDuMJuaLf4e8otAc4KQqiLINgyTxAKFOk75 VMa2L3uRFG3wU00b6OPeujEKa5FSgOeJk4aSiWvCFhX0eLLk9EJIhnziyJewP6ZgWonTbXwPRM4S a/IvZqnZmnf+a46nUel5UNca1xUW9EvSrkDUSVd5nUZYXPEnTk+fjpKvmE28YIgOJfRxb5jFVtWA revA/u6Ar5SHPpmazbcdzKYIyji8cAIoE/ASvKE5JZVgvyPzOfET0Fw/RmqWQc4OKBXLBtwbkULh N+siqkDxADGwiVvIyBB3WDyhFfM/jy3fh70jHAbo3FqHw8Qt3dluUu7P0mw1xrwE9sPTTSV9uoZE 7TrPsyaeQL57GHO1An+TkFb79UwgDWqex/1xhqV+GDLmQFFTPlHRU+gQ9iA9rU/5xa6PtyVZfGId e4E= =mSnb -----END PGP SIGNATURE----- --4QEmHYAmn97ipMvLKAVzidpTp0CzotVig--