linux-kernel - Re: [PATCH v2 0/4] drm/bridge: ti-sn65dsi86: Support EDID reading

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Message-ID: <20201101173741.GA1293305@ravnborg.org>
Date:   Sun, 1 Nov 2020 18:37:41 +0100
From:   Sam Ravnborg <sam@...nborg.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Andrzej Hajda <a.hajda@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Jonas Karlman <jonas@...boo.se>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        Douglas Anderson <dianders@...omium.org>,
        Sean Paul <seanpaul@...omium.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH v2 0/4] drm/bridge: ti-sn65dsi86: Support EDID reading

Hi Stephen.

On Thu, Oct 29, 2020 at 06:17:34PM -0700, Stephen Boyd wrote:
> This patch series cleans up the DDC code a little bit so that
> it is more efficient time wise and supports grabbing the EDID
> of the eDP panel over the aux channel. I timed this on a board
> I have on my desk and it takes about 20ms to grab the EDID out
> of the panel and make sure it is valid.
> 
> The first two patches seem less controversial so I stuck them at
> the beginning. The third patch does the EDID reading and caches
> it so we don't have to keep grabbing it over and over again. And
> finally the last patch updates the reply field so that short
> reads and nacks over the channel are reflected properly instead of
> treating them as some sort of error that can't be discerned.
> 
> Stephen Boyd (4):
>   drm/bridge: ti-sn65dsi86: Combine register accesses in
>     ti_sn_aux_transfer()
>   drm/bridge: ti-sn65dsi86: Make polling a busy loop
>   drm/bridge: ti-sn65dsi86: Read EDID blob over DDC
>   drm/bridge: ti-sn65dsi86: Update reply on aux failures

Series looks good. You can add my a-b on the full series.
Acked-by: Sam Ravnborg <sam@...nborg.org>

I can apply after Douglas have had a look at the patches he did not r-b
yet.

Any chance we can convince you to prepare this bridge driver for use in
a chained bridge setup where the connector is created by the display
driver and uses drm_bridge_funcs?

First step wuld be to introduce the use of a panel_bridge.
Then add get_edid to drm_bridge_funcs and maybe more helpers.

Then natural final step would be to move connector creation to the
display driver - see how other uses drm_bridge_connector_init() to do so
- it is relatively simple.

Should be doable - and reach out if you need some help.

	Sam

> 
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 108 ++++++++++++++++++--------
>  1 file changed, 75 insertions(+), 33 deletions(-)
> 
> Cc: Douglas Anderson <dianders@...omium.org>
> Cc: Laurent Pinchart <Laurent.pinchart@...asonboard.com>
> Cc: Jonas Karlman <jonas@...boo.se>
> Cc: Jernej Skrabec <jernej.skrabec@...l.net>
> Cc: Sean Paul <seanpaul@...omium.org>
> 
> base-commit: 3650b228f83adda7e5ee532e2b90429c03f7b9ec
> -- 
> Sent by a computer, using git, on the internet
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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