linux-kernel - Re: [PATCH 1/5] drm/omap: Fix suspend resume regression after platform data removal

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Date:   Tue, 9 Jun 2020 18:26:26 +0300
From:   Tomi Valkeinen <tomi.valkeinen@...com>
To:     Tony Lindgren <tony@...mide.com>
CC:     <linux-omap@...r.kernel.org>, "Andrew F . Davis" <afd@...com>,
        Dave Gerlach <d-gerlach@...com>,
        Faiz Abbas <faiz_abbas@...com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Grygorii Strashko <grygorii.strashko@...com>,
        Keerthy <j-keerthy@...com>, Nishanth Menon <nm@...com>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Roger Quadros <rogerq@...com>, Suman Anna <s-anna@...com>,
        Tero Kristo <t-kristo@...com>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <dri-devel@...ts.freedesktop.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH 1/5] drm/omap: Fix suspend resume regression after
 platform data removal

On 09/06/2020 18:19, Tony Lindgren wrote:

>> But there's an extra runtime PM reference (dev.power.usage_count) that seems
>> to come out of nowhere. So when omap_drm_suspend is finished, there's still
>> usage_count of 1, and dispc never suspends fully.
> 
> Hmm no idea about that. My guess is that there might be an issue that was
> masked earlier with omap_device calling the child runtime_suspend.

Yes. It's how PM works. It calls pm_runtime_get_noresume() before starting the suspend of a device. 
So I guess omapdrm's suspend has been broken all the time, but it was "fixed" by omap_device.

> Currently I'm only able to rmmod -f omapdrm, not sure if these issues might
> be related.

Hmm, I always use modules, and can unload omapdrm and drm fine. But there's a sequence that must be 
followed. However, the sequence starts with unloading omapdrm... What behavior you see with rmmod?

  Tomi

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