linux-kernel - Re: [PATCH 08/10] drm/tidss: Add dispc_is

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Message-ID: <e42af7bf-2f73-49ce-b192-1a6582bc81bd@ideasonboard.com>
Date:   Thu, 2 Nov 2023 09:03:20 +0200
From:   Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     Aradhya Bhatia <a-bhatia1@...com>,
        Devarsh Thakkar <devarsht@...com>,
        Jyri Sarha <jyri.sarha@....fi>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 08/10] drm/tidss: Add dispc_is_idle()

On 01/11/2023 16:32, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Wed, Nov 01, 2023 at 11:17:45AM +0200, Tomi Valkeinen wrote:
>> Add a helper function, dispc_is_idle(), which returns whether the DSS is
>> idle (i.e. is any video port enabled).
>>
>> For now we add a call to it in the suspend and resume callbacks, and
>> print a warning if in either place the DSS is not idle.
> 
> Could you please explain here why these checks are needed/useful ? Why
> would the dispc not be idle ?

I'll drop this. This was mostly a debugging aid for myself when testing 
runtime PM.

  Tomi