From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from galahad.ideasonboard.com ([185.26.127.97]:41710 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752941AbcLMV2N (ORCPT ); Tue, 13 Dec 2016 16:28:13 -0500 From: Laurent Pinchart To: Daniel Vetter Cc: Laurent Pinchart , dri-devel@lists.freedesktop.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH v2] drm: shmobile: Perform initialization/cleanup at probe/remove time Date: Tue, 13 Dec 2016 23:28:44 +0200 Message-ID: <3406417.RXamfUdFgG@avalon> In-Reply-To: <20161213210136.dh5qfzgt55lzjr5x@phenom.ffwll.local> References: <20161213084300.5kvq6ymgrkqldf3t@phenom.ffwll.local> <2835101.vUU6uQBUMJ@avalon> <20161213210136.dh5qfzgt55lzjr5x@phenom.ffwll.local> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: Hi Daniel, On Tuesday 13 Dec 2016 22:01:36 Daniel Vetter wrote: > On Tue, Dec 13, 2016 at 07:19:15PM +0200, Laurent Pinchart wrote: > > On Tuesday 13 Dec 2016 18:11:34 Daniel Vetter wrote: > >> On Tue, Dec 13, 2016 at 02:59:48PM +0200, Laurent Pinchart wrote: > >>> From: Laurent Pinchart > >>> > >>> The drm driver .load() operation is prone to race conditions as it > >>> initializes the driver after registering the device nodes. Its usage > >>> is deprecated, inline it in the probe function and call > >>> drm_dev_alloc() and drm_dev_register() explicitly. > >>> > >>> For consistency inline the .unload() handler in the remove function as > >>> well. > >>> > >>> Signed-off-by: Laurent Pinchart > >>> Acked-by: Daniel Vetter > >>> --- > >>> Changes since v1: > >>> > >>> - Removed manual the drm_connector_register() that caused > >>> sysfs-related warnings > >> > >> Hm, what did go boom there? We should catch multiple calls to > >> drm_connector_register ... > > > > Trying to register the connector before the DRM device is registered makes > > sysfs unhappy due to the lack of a parent. > > Autch. I think for i915 we're safe though - our trouble is that mst > hotplug starts to happen before we call drm_dev_register (but it's still > safe there already), because atm the initial topology detection works out > to be async. But we already have the drm_device at least initialized, > which I guess with DT and probe-defer isn't guaranteed. > > Or does this even go boom if you just register a child before the parent? I think it does, but I haven't investigated this any further. Given that we have support for auto-registration of connectors at drm_device registration time, and that I don't need to register connectors later, I just went the easy way. For connectors that can be registered at any time, something more elaborate is likely needed. > >>> drivers/gpu/drm/shmobile/shmob_drm_crtc.c | 7 +- > >>> drivers/gpu/drm/shmobile/shmob_drm_drv.c | 206 ++++++++++------------- > >>> 2 files changed, 104 insertions(+), 109 deletions(-) -- Regards, Laurent Pinchart