linux-kernel - Re: [PATCH v2 3/3] drm/panel-edp: Allow querying the detected panel via debugfs

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Message-ID: <d875e70c-e9a9-9e4d-7041-f8ff6ee48f4f@redhat.com>
Date:   Tue, 15 Feb 2022 23:10:12 +0100
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     Douglas Anderson <dianders@...omium.org>,
        dri-devel@...ts.freedesktop.org
Cc:     Daniel Vetter <daniel@...ll.ch>, robert.foss@...aro.org,
        lschyi@...omium.org, Sam Ravnborg <sam@...nborg.org>,
        jjsu@...omium.org, David Airlie <airlied@...ux.ie>,
        Thierry Reding <thierry.reding@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] drm/panel-edp: Allow querying the detected panel
 via debugfs

On 2/5/22 01:13, Douglas Anderson wrote:
> Recently we added generic "edp-panel"s probed by EDID. To support
> panels in this way we look at the panel ID in the EDID and look up the
> panel in a table that has power sequence timings. If we find a panel
> that's not in the table we will still attempt to use it but we'll use
> conservative timings. While it's likely that these conservative
> timings will work for most nearly all panels, the performance of
> turning the panel off and on suffers.
> 
> We'd like to be able to reliably detect the case that we're using the
> hardcoded timings without relying on parsing dmesg. This allows us to
> implement tests that ensure that no devices get shipped that are
> relying on the conservative timings.
> 
> Let's add a new debugfs entry to panel devices. It will have one of:
> * UNKNOWN - We tried to detect a panel but it wasn't in our table.
> * HARDCODED - We're not using generic "edp-panel" probed by EDID.
> * A panel name - This is the name of the panel from our table.
> 
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---

Reviewed-by: Javier Martinez Canillas <javierm@...hat.com>

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat