Re: [PATCH v1 2/2] drm/tegra: Use drm_dp_aux_register_ddc/chardev() helpers

From: Dmitry Osipenko <digetx@gmail.com>
To: Lyude Paul <lyude@redhat.com>, Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@linux.ie>,
	Thomas Graichen <thomas.graichen@gmail.com>,
	dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/2] drm/tegra: Use drm_dp_aux_register_ddc/chardev() helpers
Date: Fri, 12 Nov 2021 23:45:36 +0300	[thread overview]
Message-ID: <9d7c2ff8-c154-b1e8-a7c5-c7f63aa5474f@gmail.com> (raw)
In-Reply-To: <be1833c5d27e666b760c729fc112d1bbd7b7a269.camel@redhat.com>

12.11.2021 23:26, Lyude Paul пишет:
>> BTW, I see now that DPAUX I2C transfer helper may access
>> aux->drm_device. Hence v1 patch isn't correct anyways.
> 
> JFYI - unless I'm misunderstanding you, the aux->drm_dev accesses in the DPAUX
> i2c transfer functions are just from the various drm_{dbg,err,etc.} calls,
> which means that they all should be able to handle aux->drm_dev being NULL. If
> you can set aux->drm_dev before i2c transfers start that's more ideal, since
> otherwise you'll see the AUX device name as "(null)" in the kernel log, but
> any point before device registration should work.

Thanks, I realized that have seen DRM log with a such debug messages
just a day ago.

drm drm: [drm:drm_dp_i2c_do_msg] (null): transaction timed out

So yes, it's indeed not critical.