From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162923AbdDUWxf (ORCPT ); Fri, 21 Apr 2017 18:53:35 -0400 Received: from anholt.net ([50.246.234.109]:46402 "EHLO anholt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161358AbdDUWxd (ORCPT ); Fri, 21 Apr 2017 18:53:33 -0400 From: Eric Anholt To: Daniel Vetter Cc: dri-devel , Rob Herring , Mark Rutland , "devicetree\@vger.kernel.org" , Linux Kernel Mailing List Subject: Re: [PATCH 2/3] drm/vc4: Don't try to initialize FBDEV if we're only bound to V3D. In-Reply-To: References: <20170418191157.18517-1-eric@anholt.net> <20170418191157.18517-2-eric@anholt.net> <8760i046zw.fsf@eliezer.anholt.net> User-Agent: Notmuch/0.22.2+1~gb0bcfaa (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Fri, 21 Apr 2017 15:53:30 -0700 Message-ID: <87wpadtlsl.fsf@eliezer.anholt.net> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: text/plain Daniel Vetter writes: > On Wed, Apr 19, 2017 at 7:55 PM, Eric Anholt wrote: >> Daniel Vetter writes: >>> On Tue, Apr 18, 2017 at 9:11 PM, Eric Anholt wrote: >>>> The FBDEV initialization would throw an error in dmesg, when we just >>>> want to silently not initialize fbdev on a V3D-only VC4 instance. >>>> >>>> Signed-off-by: Eric Anholt >>> >>> Hm, this shouldn't be an error really, you might want to hotplug more >>> connectors later on. What exactly complains? >> >> drm_fb_helper_init() throws an error if the passed in connector count is >> 0, so drm_fb_cma_helper() printks an error. > > Oh, _that_ thing. The error in there is correct, but (almost) everyone > gets this parameter wrong. This isn't the max number of connectors the > fb helper will light up, but just the max number of connectors _per_ > crtc when driving in hw clone mode. There's two problems with that: > - fb helpers don't support hw clone mode, we select 1:1 crtcs for each > active connector > - I mentioned that everyone gets this wrong? > > If you're moderately bored it'd be great to nuke the max_connector > argument from drm_fb_helper_init, and hard-code it to 1 (with a big > comment explaining that this needs to be changed, probably with > dynamic reallocation, once someone gets around to implementing hw > clone mode). > > If you're less bored, just hardcode this to 1 in vc4 and done. Plus a > TODO.rst entry would be great in that case. If I'm driving a GPU with no display subsystem at all, it seems like I shouldn't initialize fbdev for it, right? --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE/JuuFDWp9/ZkuCBXtdYpNtH8nugFAlj6jWoACgkQtdYpNtH8 nuhrqw/+JRZuhfaLORI8+ALYPoCHs+JQ7TvbIYAl64AY9uA266MTlr8Z+kIBYePJ IuTG0S8kt6r+DzdGlppTEZvGDdFExPx+VGpkT4AD/yn3zSxXiOQkZc987sz/IaIK QJLcXgpYrAnFCEkBSHnrr8weQQEykvh9CRiB9YK0iRKWNNpbgzZGlA6XDaoICZNW PUSCwhG3y/x9/2p1fFg/AWhsaoMov2HvLXEwwpJrL/sdeolO0fVWdJHMYXgnbLHx ali2aTYgiRYM+1CqKZvdgZkFvdhGg6GBF1GsOpYhnOPFppKq6VE+mUYltaUDh3Jy +mH6hv6lk5b5fLKJ9nCdtinzfL6A3Occ6TRHj52cYNI8zCC5kYPpaKHIfJTBcCcO uCsGeLIg1bl5e/QjyrSTdZeQEwrd95T4qUF3Oqj1n2qzeS7Dpi8etZuaaMh9pvGR IUgzoMCvv6uw66qQnI4/qDmqRjzDguhlfcmi13F4qkidrvgG2MgKxZY48IgWbLvD jztGkxbWuWxNzpOjgV/ui7dfIxQC5F4T07p+N2NTiAnQSG3E5RnPxzXcGwkoxL7n A6+cxn+Yzw8lxjV1YMnG4UNLfLUNqdIHkidBGYwFHsy+AS2OH0RxltU5jy0HRzxB dqJxJbIZZT/pss5DOpjPYHLPz9ljqt33k2JAi6ANbwEDcG3xK3I= =oBkM -----END PGP SIGNATURE----- --=-=-=--