From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anholt Subject: Re: [PATCH v3 0/4] drm/panel: Handle the "panel is missing" case properly Date: Wed, 11 Jul 2018 09:20:12 -0700 Message-ID: <87tvp5iw1v.fsf@anholt.net> References: <20180509130042.9435-1-boris.brezillon@bootlin.com> <20180710091904.GA1504@ulmo> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1535101755==" Return-path: Received: from anholt.net (anholt.net [50.246.234.109]) by gabe.freedesktop.org (Postfix) with ESMTP id 8CE7F6ED43 for ; Wed, 11 Jul 2018 16:20:16 +0000 (UTC) In-Reply-To: <20180710091904.GA1504@ulmo> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Thierry Reding , Boris Brezillon Cc: David Airlie , dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============1535101755== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Thierry Reding writes: > [ Unknown signature status ] > On Wed, May 09, 2018 at 03:00:38PM +0200, Boris Brezillon wrote: >> Hello, >>=20 >> This is a new attempt at fixing the "panel is missing" issue (described >> in this thread [1]). I lost track of Eric's proposal, but I recently >> proposed to address this problem through a new ->detect() hook in the >> panel_funcs interface [2], which was rejected. >>=20 >> So here is a new version based on the feedback I had from Daniel, >> Thierry and Rob. >>=20 >> The idea is to allow of_drm_find_panel() to return -ENODEV and let the >> DRM driver decide what to do with that (silently ignore the missing >> component and register the DRM device, or fail to register the DRM >> device). >>=20 >> Patch 1 changes the semantic of of_drm_find_panel() so that it returns >> an ERR_PTR() instead of NULL when the panel is not found. This way >> we'll be able to differentiate the "panel is missing" from "panel has >> not been probed yet" errors. >>=20 >> Patch 2 and 3 are adding new tests in of_drm_find_panel() and >> drm_of_find_panel_or_bridge() to return -ENODEV when the status >> property of the DT node is not set to "okay". >>=20 >> Patch 4 is patching the VC4 DSI encoder driver to gracefully handle the >> -ENODEV case and allow the registration of the DRM device when the DSI >> device is disabled. >>=20 >> Note that patch 6 which was modifying the panel status prop from the >> I2C driver has been dropped because I'm not sure yet how to solve the >> "force probe of deferred-probe devices even if no new devices have been >> bound to drivers" problem. Anyway, even without this patch, the series >> still makes sense to handle the case where devices are described in the >> DT but marked "disabled" (either at compilation time or tweaked by the >> bootloader). >>=20 >> Regards, >>=20 >> Boris >>=20 >> Changes in v3: >> - Dropped patch 1 since it's been acked by Thierry and should be >> applied soon (either through the drm-tegra or drm-misc tree) >> - Dropped patch 6 because we are still discussing who should mark >> the device "disabled" or "fail" and how we should trigger the >> re-probe of deferred-probe devices in this case >>=20 >> Changes in v2: >> - Everything :-) >>=20 >> [1]https://lists.freedesktop.org/archives/dri-devel/2017-November/157688= .html >> [2]https://www.spinics.net/lists/dri-devel/msg174808.html > > I don't exactly remember what we decided should be the merge path for > this, but I suspect someone else was supposed to pick it up because I > ended up acking these patches. However, since this hasn't been applied > yet, I decided to go ahead and apply this to drm-misc-next. Since you'd been engaged on previous versions, I was waiting for an ack on patch 1. Thanks for taking care of this now! --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE/JuuFDWp9/ZkuCBXtdYpNtH8nugFAltGLjwACgkQtdYpNtH8 nuitsQ//av/X4BoSWpT04tm9V0HlZ0CwcaThU3DDIZgiBhNJOh071Ma/eT9MPsx/ y7KkpXbKzfORa9HoUwdDBAvwIcWhfYjCfsxdaQJ237d93gztxgIb7DhT8SpqUcYf 8kPNR8tmdEeo9ujXhjW2o2xML11hoKItmAoCCRK9Vo4fAAuPgGqqYFb+v2D99zjO v/vUHq6Rl62EYMH2ey0HsyKNmIwtcziFUllbwAcCyXPIwIyMS1EM3ODADTjNreut fUY7f3A/Wd362BQrS2ZRHzgyDe4vVE1K7ox8UEs95WvRNiL6e8Oiw2NTaGuVoRhd SU9YV5aQQgeBLkC5zTZ8rMdLSK1fSXRvtXjdYm16n9/HJUsjfrAZHoAx1IpVXABN +yxIGBjnMCnIASTtNZMrbQXLt/p+GJ4rzrAEPV7Z01ulqUQ+jfjLWRPz+ZGjOdJa arScDYVG93PybG1uaOB3t+XfETdZji3R91wWpPwXNeIXkpjA9mD0B9/+E6Dt0nj4 FMKtvSWA39qJQfpGf9d8J5Pfmh/D7ArNErFrFfs2UHiQECrefR13CKV1nQo+7MCu g0g9epLKImifPAYp98pHp2oI+AD89x/KOatqGzIng2rotSaycZv3QZ6i4Auh4run p+LFFdgTBmGQDIKgQyQZ4/ZVRJf5sbtQl8/h2QvIHAR9WDphdbc= =aDa9 -----END PGP SIGNATURE----- --=-=-=-- --===============1535101755== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============1535101755==--