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Message-ID: <f62174cf-5786-f9d0-3a3a-3c9919f27b1e@samsung.com>
Date:   Fri, 29 Oct 2021 10:36:00 +0200
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Subject: Re: [v6,02/21] drm/bridge: adv7511: Register and attach our DSI
 device at probe
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To:     Maxime Ripard <maxime@cerno.tech>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Robert Foss <robert.foss@linaro.org>,
        Jonas Karlman <jonas@kwiboo.se>,
        Daniel Vetter <daniel.vetter@intel.com>,
        David Airlie <airlied@linux.ie>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Seung-Woo Kim <sw0312.kim@samsung.com>,
        linux-arm-msm@vger.kernel.org,
        Joonyoung Shim <jy0922.shim@samsung.com>,
        Rob Clark <robdclark@gmail.com>,
        Tian Tao <tiantao6@hisilicon.com>,
        Chen Feng <puck.chen@hisilicon.com>,
        Xinwei Kong <kong.kongxinwei@hisilicon.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        linux-samsung-soc@vger.kernel.org,
        Xinliang Liu <xinliang.liu@linaro.org>,
        John Stultz <john.stultz@linaro.org>,
        linux-kernel@vger.kernel.org, Inki Dae <inki.dae@samsung.com>,
        dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
        Sean Paul <sean@poorly.run>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
In-Reply-To: <20211029080521.6tmfq4kjngu5slv7@gilmour>
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References: <20211025151536.1048186-3-maxime@cerno.tech>
        <CGME20211029062347eucas1p1431402205321b066349e3ccf432d2452@eucas1p1.samsung.com>
        <73c13cf5-ca36-f47b-f53a-11d4f015505c@samsung.com>
        <20211029080521.6tmfq4kjngu5slv7@gilmour>
Precedence: bulk

Hi Mexime,

On 29.10.2021 10:05, Maxime Ripard wrote:
> On Fri, Oct 29, 2021 at 08:23:45AM +0200, Marek Szyprowski wrote:
>> On 25.10.2021 17:15, Maxime Ripard wrote:
>>> In order to avoid any probe ordering issue, the best practice is to move
>>> the secondary MIPI-DSI device registration and attachment to the
>>> MIPI-DSI host at probe time. Let's do this.
>>>
>>> Acked-by: Sam Ravnborg <sam@ravnborg.org>
>>> Tested-by: John Stultz <john.stultz@linaro.org>
>>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>> This patch landed in linux-next as commit 864c49a31d6b ("drm/bridge:
>> adv7511: Register and attach our DSI device at probe"). Sadly it causes
>> endless probe-fail-defer loop on DragonBoard 410c board
>> (arch/arm64/boot/dts/qcom/apq8016-sbc.dts):
> I'm sorry to hear that (but would have been surprised if it didn't occur)
>
> This is supposed to be fixed by 8f59ee9a570c ("drm/msm/dsi: Adjust probe
> order"). Do you have that patch applied?

Yes, I did my test directly on linux next-20211028, which also contains 
it. What might be important in my case, my DragonBoard 410c doesn't have 
any display attached.

I've also noticed the following error during boot:

[   23.847651] msm_mdp 1a01000.mdp: Adding to iommu group 3
[   23.866044] msm_mdp 1a01000.mdp: No interconnect support may cause 
display underflows!
[   23.957949] irq: no irq domain found for mdss@1a00000 !
[   23.958014] msm_dsi 1a98000.dsi: failed to request IRQ0: -22
[   23.962229] msm_dsi: probe of 1a98000.dsi failed with error -22

The above errors appeared in next-20211028 for the first time. I assume 
that they are related.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland