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 9AAE8C64E7C for ; Wed, 2 Dec 2020 07:56:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 401EB2065C for ; Wed, 2 Dec 2020 07:56:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727041AbgLBH4f (ORCPT ); Wed, 2 Dec 2020 02:56:35 -0500 Received: from mx2.suse.de ([195.135.220.15]:50358 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726148AbgLBH4f (ORCPT ); Wed, 2 Dec 2020 02:56:35 -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 B3654AC2D; Wed, 2 Dec 2020 07:55:53 +0000 (UTC) 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> From: Thomas Zimmermann Subject: Re: [PATCH] fbdev: Remove udlfb driver Message-ID: <9e7cad29-a9c0-2e02-04a9-3149d7e15838@suse.de> Date: Wed, 2 Dec 2020 08:55:52 +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: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="DyF5ErOOQxZapjJT3Ag8XB7gJoy8VMU4t" Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --DyF5ErOOQxZapjJT3Ag8XB7gJoy8VMU4t Content-Type: multipart/mixed; boundary="PCdFIN2iawhSKjj8GO2dskStC23JJYou5"; 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: <9e7cad29-a9c0-2e02-04a9-3149d7e15838@suse.de> Subject: Re: [PATCH] fbdev: Remove udlfb driver References: <20201130125200.10416-1-tzimmermann@suse.de> <20201130154147.GT401619@phenom.ffwll.local> In-Reply-To: --PCdFIN2iawhSKjj8GO2dskStC23JJYou5 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Hi Am 01.12.20 um 12:20 schrieb Mikulas Patocka: >=20 >=20 > On Tue, 1 Dec 2020, Thomas Zimmermann wrote: >=20 >> 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 direct= ly on >>>>> the framebuffer console, such as web browser "links -g", image view= er >>>>> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl= ", >>>>> 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 cle= ar 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.htm= l >>> >>> But the patch never went through and the fb_defio feature was removed= in >>> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa). >>> >>> >>> Without fb_defio, the only other possibility how to update the screen= is >>> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode= , so >>> user programs like "links -g" can't issue it. >> >> That's confusing. DIRTYFB is only for DRM. >=20 > Yes, you're right. >=20 >> And why can links not run as DRM master mode? If it renders to the ter= minal, >> it should act like a composer. In that case it almost certainly wants = master >> status. >> >> Best regards >> Thomas >=20 > How can a userspace program acquire master mode without being suid? For my understanding, there's no easy solution to that. :/ I guess we (DRM devs) have to treat fbdev as the solution for use cases=20 such as ours. For the unplug issue, I'll try to reproduce and fix it. For the performance problems, we might be able to squeeze a few more=20 cycles out of it. Best regards Thomas >=20 > Is there some "Hello World!" program that shows how to use DRM? I'm not= an > expert in DRM, but if there were some tutorial+documentation, I could > consider porting "links" to it. >=20 > 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 --PCdFIN2iawhSKjj8GO2dskStC23JJYou5-- --DyF5ErOOQxZapjJT3Ag8XB7gJoy8VMU4t 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/HSIgFAwAAAAAACgkQlh/E3EQov+De rRAAuiguOHT9X8o4OXxwH/edemSGzFmzaNQmrA/4rW8QIuym1UdDLWsCuHA1lwJzRCPmHMeYnACK 77jE/lKogeZtRMgfWh4UlN5o09oVZjRzHbX42vFxwgJBOu5cmB8bkKj20eC0JFZZ62evLT6SLla/ eRWqv0OFjZXM6Q/Qv6a5DDoEa56slbdE56sadbex7lGWNQ3VdYy+fx19UhsDtbkaxY4XkWlkGFvH N5RtYgIPPOTGaCeVC5G3sTs9fymf1P4K7C9v3tNyFgQ+mBDGen80XAkpxzglH1TVc1ewidhZ/zmJ M4HppnegjC6xYIvpV3ATk1Ec9HeOn/3lsuYri42Xe2sPVIJPtu53z/a2ph3kp+zajdnYCGqS5FFX N/UE84LrSvrtBskNBO97RDKNaQ4v4JVVeRqZQ3UqD6saiZZenO1KMJYZNeJZewLBbZIcJK3V4I4K bMkcyKBLvZg7HNgXDLikLfhyB5FHyng2GXWC/NlzSDGqqQRagi80xX1V9YM0LRd9/SgPuBBYUGoa dQe1adAUP12eL3u69JB2b6sKEB3/dUPAsyQWAEsv0xplkBuTp5/AJh8iC61qmta6JQVJWqadBtR/ ja5aymitqclPi5cm5cztVi+FRZyj5xr2TmtdMzOnlOupIO3ICCinOy7EB406QvmMXMdDHez9b44g vcE= =46Cv -----END PGP SIGNATURE----- --DyF5ErOOQxZapjJT3Ag8XB7gJoy8VMU4t--