linux-kernel - Re: [PATCH v3 10/10] arm64: dts: renesas: gray-hawk-single: Add DisplayPort support

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Message-ID: <631bda4c-2226-4693-bcb8-a64872533c6c@ideasonboard.com>
Date: Mon, 16 Dec 2024 17:15:20 +0200
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
 Andrzej Hajda <andrzej.hajda@...el.com>,
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>,
 Geert Uytterhoeven <geert+renesas@...der.be>,
 Magnus Damm <magnus.damm@...il.com>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, LUU HOAI <hoai.luu.ub@...esas.com>,
 Jagan Teki <jagan@...rulasolutions.com>, Sam Ravnborg <sam@...nborg.org>,
 Biju Das <biju.das.jz@...renesas.com>, dri-devel@...ts.freedesktop.org,
 linux-renesas-soc@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
 linux-clk@...r.kernel.org,
 Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
Subject: Re: [PATCH v3 10/10] arm64: dts: renesas: gray-hawk-single: Add
 DisplayPort support

Hi,

On 16/12/2024 15:33, Geert Uytterhoeven wrote:
> Hi Tomi,
> 
> On Fri, Dec 6, 2024 at 10:33 AM Tomi Valkeinen
> <tomi.valkeinen@...asonboard.com> wrote:
>> From: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
>>
>> Add support for the mini DP output on the Gray Hawk board.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
>> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
>> Tested-by: Geert Uytterhoeven <geert+renesas@...der.be>
> 
> Thanks for your patch, which is now commit b1000645dc29701f
> ("arm64: dts: renesas: gray-hawk-single: Add DisplayPort support")
> in renesas-devel/renesas-dts-for-v6.14.
> 
> Apparently this patch breaks s2idle on Gray Hawk Single when "[PATCH
> v3 06/10] drm/rcar-du: dsi: Add r8a779h0 support" is not present, or
> when CONFIG_DRM_RCAR_USE_MIPI_DSI is not enabled. If the DSI driver
> is not available, the ti_sn65dsi86.bridge part fails to probe with
> -EPROBE_DEFER and "failed to attach dsi host".  Still, the sn65dsi86
> driver must do something critical, as resuming from s2idle now hangs.
> I haven't identified yet where exactly it hangs.
> > As a result, s2idle is broken in current renesas-devel, which only
> has the DTS changes.  Perhaps I should drop the DTS until the issue
> is resolved?

I'm fine with that. The DT bindings are still under work anyway.

> However, I suspect White Hawk has the same issue (if
> CONFIG_DRM_RCAR_USE_MIPI_DSI=n), but I cannot verify as my local White
> Hawk is currently not available for kernel testing.

I can reproduce on White Hawk. And I agree that it's probably related to 
sn65dsi86.

I use modules, so I tried dropping modules to see when the issue goes 
away. And it's always sn65dsi86. So without the rcar DRM & DSI modules 
loaded, if I load or don't load sn65dsi86, I see or don't see the hang, 
respectively.

Even if I drop the ti_sn65dsi86_pm_ops, it doesn't help. And looks like 
just doing the i2c_add_driver() part in ti_sn65dsi86_init() will cause 
the issue, so it's something that happens there.

I'll continue the debug later.

  Tomi