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Date:   Wed, 12 Jul 2023 19:25:40 +0200
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Subject: Re: [PATCH v4 3/3] drm/panel-fannal-c3004: Add fannal c3004 DSI panel
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To:     Paulo Pavacic <pavacic.p@gmail.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Jagan Teki <jagan@amarulasolutions.com>,
        Maya Matuszczyk <maccraft123mc@gmail.com>,
        neil.armstrong@linaro.org, sam@ravnborg.org, airlied@gmail.com,
        daniel@ffwll.ch, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org
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From:   Marek Vasut <marex@denx.de>
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On 7/12/23 17:10, Paulo Pavacic wrote:

Hi,

[...]

>>>> Or whether it makes sense to outright have a separate driver. The later
>>>> would introduce duplication, but maybe that much duplication is OK.
>>>
>>> I would like to create new driver because panel-st7701 seems to be
>>> outdated and is using non-standard macro (ST7701_WRITE()
>>
>> There is no such macro:
>>
>> $ git grep ST7701_WRITE drivers/gpu/drm/panel/ | wc -l
>> 0
>>
>> There never was such a macro used in the driver either, are you sure you
>> are not using some hacked up patched downstream fork of the driver ?
> 
> I meant ST7701_DSI() macro; It can be replaced with
> mipi_dsi_generic_write_seq from kernel 6.3. Sorry for the confusion.

OK

>> $ git log -p next/master --
>> drivers/gpu/drm/panel/panel-sitronix-st7701.c | grep ST7701_WRITE | wc -l
>> 0
>>
>>> ) and for me
>>> it is crashing kernel 5.15.
>>
>> Have you based all the aforementioned discussion and argumentation on
>> year and half old Linux 5.15.y code base too ?
>>
>> If so, you are missing many patches:
>>
>> $ git log --oneline --no-merges v5.15..next/master --
>> drivers/gpu/drm/panel/panel-sitronix-st7701.c
>> 5a2854e577dc2 drm: panel: Add orientation support for st7701
>> e89838968ee44 drm: panel: Add Elida KD50T048A to Sitronix ST7701 driver
>> c62102165dd79 drm/panel/panel-sitronix-st7701: Remove panel on DSI
>> attach failure
>> 49ee766b364ed drm/panel/panel-sitronix-st7701: Clean up CMDnBKx selection
>> c1cdee9b685a1 drm/panel/panel-sitronix-st7701: Fix RTNI calculation
>> 57b2efce45ef5 drm/panel/panel-sitronix-st7701: Add Densitron
>> DMT028VGHMCMI-1A TFT
>> 42542c7904cf2 drm/panel/panel-sitronix-st7701: Split GIP and init sequences
>> 83b7a8e7e88e7 drm/panel/panel-sitronix-st7701: Parametrize voltage and
>> timing
>> de2b4917843cd drm/panel/panel-sitronix-st7701: Infer horizontal pixel
>> count from TFT mode
>> 82f9cee25598a drm/panel/panel-sitronix-st7701: Adjust porch control
>> bitfield name
>> 1ba85119afb5e drm/panel/panel-sitronix-st7701: Infer vertical line count
>> from TFT mode
>> 779c84fea3dbd drm/panel/panel-sitronix-st7701: Make gamma correction TFT
>> specific
>> 7fa8e07128ed6 drm/panel/panel-sitronix-st7701: Make voltage supplies
>> common to ST7701
>> a6c225be3da7e drm/panel/panel-sitronix-st7701: Enable DSI burst mode,
>> LPM, non-continuous clock
>> 6f481afe220d3 drm/panel/panel-sitronix-st7701: Make DSI mode flags
>> common to ST7701
>> 79abca2b39900 drm/mipi-dsi: Make remove callback return void
> 
> I will try backporting those patches to 5.15 and applying them to see
> whether it will then work with initialization sequences provided in
> this merge request just to be sure not to have duplication. We are
> still working on transitioning to newer kernel so for the time being
> I'm using mostly 5.15.
> 
> On 5.15 kernel I have following kernel panic only with st7701 from the
> panel drivers I have tried:
> 
> [   20.255322] Kernel panic - not syncing: Asynchronous SError Interrupt
> [   20.255326] CPU: 1 PID: 36 Comm: kworker/1:1 Tainted: G           O
>       5.15.77-5.15.77-2.1.0 #1

The latest 5.15.y is 5.15.120 , can you re-test on that version ?

> [   20.255330] Hardware name: XXX i.MX8XX board:XXX (DT)

Is this some NXP downstream kernel fork with thousands of extra patches?
The version string 2.1.0 looks very much like NXP versioning scheme ...

[...]