Date: Thu, 20 Jul 2017 14:08:29 +0100
From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Liviu Dudau <Liviu.Dudau@arm.com>
Cc: David Airlie <airlied@linux.ie>,
        DRI devel <dri-devel@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drm/i2c: tda998x: Fix lockdep warning about possible
 circular dependency
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On Thu, Jul 20, 2017 at 01:54:04PM +0100, Liviu Dudau wrote:
> On Thu, Jul 20, 2017 at 12:44:49PM +0100, Russell King - ARM Linux wrote:
> > Actually, scrub that idea - drm_helper_probe_single_connector_modes()
> > calls drm_edid_to_eld() for these cases anyway, so we must call
> > drm_helper_probe_single_connector_modes() with the audio_mutex held.
> 
> OK, so the lockdep warning is spurious?

I don't think so.  I think there's two ways to solve this:

1. replace the audio_mutex in tda998x_audio_get_eld() and
   tda998x_connector_fill_modes() with a new mutex (eld_mutex) to
   protect just the ELD.

2. remove the mutex from these two functions, and take the connection_mutex
   modeset lock in tda998x_audio_get_eld().

However, I don't have a view on which would be best.

-- 
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