Re: [PATCH 5/6] phy: qcom-qmp-combo: fix drm bridge registration

From: Vinod Koul <vkoul@kernel.org>
To: Johan Hovold <johan+linaro@kernel.org>
Cc: Bjorn Andersson <andersson@kernel.org>,
	Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
	Jonas Karlman <jonas@kwiboo.se>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Rob Clark <robdclark@gmail.com>,
	Abhinav Kumar <quic_abhinavk@quicinc.com>,
	Kuogee Hsieh <quic_khsieh@quicinc.com>,
	freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-phy@lists.infradead.org, stable@vger.kernel.org,
	Bjorn Andersson <quic_bjorande@quicinc.com>
Subject: Re: [PATCH 5/6] phy: qcom-qmp-combo: fix drm bridge registration
Date: Fri, 23 Feb 2024 17:39:45 +0530	[thread overview]
Message-ID: <ZdiLCYKCujs4DgKV@matsya> (raw)
In-Reply-To: <20240217150228.5788-6-johan+linaro@kernel.org>

On 17-02-24, 16:02, Johan Hovold wrote:
> Due to a long-standing issue in driver core, drivers may not probe defer
> after having registered child devices to avoid triggering a probe
> deferral loop (see fbc35b45f9f6 ("Add documentation on meaning of
> -EPROBE_DEFER")).
> 
> This could potentially also trigger a bug in the DRM bridge
> implementation which does not expect bridges to go away even if device
> links may avoid triggering this (when enabled).
> 
> Move registration of the DRM aux bridge to after looking up clocks and
> other resources.
> 
> Note that PHY creation can in theory also trigger a probe deferral when
> a 'phy' supply is used. This does not seem to affect the QMP PHY driver
> but the PHY subsystem should be reworked to address this (i.e. by
> separating initialisation and registration of the PHY).

Acked-by: Vinod Koul <vkoul@kernel.org>

-- 
~Vinod