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Message-ID: <869d0e2c-b04a-ef35-cfe5-b372c646fce9@redhat.com>
Date:   Mon, 8 Nov 2021 08:55:53 +0100
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Subject: Re: [BUG 5/5] [BUG] media: atomisp: atomisp causes touchscreen to
 stop working on Microsoft Surface 3
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To:     Mauro Carvalho Chehab <mchehab@kernel.org>
Cc:     Tsuchiya Yuto <kitakar@gmail.com>,
        Patrik Gfeller <patrik.gfeller@gmail.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Kaixu Xia <kaixuxia@tencent.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Arnd Bergmann <arnd@arndb.de>, linux-media@vger.kernel.org,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
References: <20211017162337.44860-1-kitakar@gmail.com>
 <20211017162337.44860-6-kitakar@gmail.com>
 <103b5438-9f7c-7e89-28b9-29fe11eb818c@redhat.com>
 <cfad27a4bfdd94417305e1519e2f450a4422844d.camel@gmail.com>
 <310ace44-93d5-99a3-bb4c-371b0a13462d@redhat.com>
 <20211108074101.033af4c5@sal.lan>
From:   Hans de Goede <hdegoede@redhat.com>
In-Reply-To: <20211108074101.033af4c5@sal.lan>
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Hi Mauro,

On 11/8/21 08:41, Mauro Carvalho Chehab wrote:
> Em Mon, 8 Nov 2021 00:39:38 +0100
> Hans de Goede <hdegoede@redhat.com> escreveu:
> 
>> Hi,
>>
>> On 10/21/21 11:52, Tsuchiya Yuto wrote:
>>> Thank you for your comment :-)
>>>
>>> First, I need to correct what I said in the previous mail. I later found
>>> that loading only "atomisp" (as well as its dependency,
>>> atomisp_gmin_platform) does not cause this issue.
>>>
>>> What causes this issue is rather, loading sensor drivers (as well as its
>>> dependency, atomisp_gmin_platform).
>>>
>>> These sensor drivers for surface3 are both not upstream, but I made them
>>> as similar as possible to the upstreamed ones. So, I guess this issue
>>> can still be reproducible on some other devices.  
>>
>> I've run some test on my own surface3 and the problem is the writing
>> of 0x62 (which becomes just 0x02) to the 0x57 register of the PMIC,
>> writing 0x00 to that after loading the sensor driver makes things work
>> again.
>>
>> I have not had time to investigate this further.
>>
>> I used media-staging + your sensor drivers from:
>> https://github.com/kitakar5525/surface3-atomisp-cameras.git
>>
>> Which was enough to figure this out, but I've not actually gotten
>> either of the cameras working :|  I get:
>>
>> [user@fedora nvt]$ ./atomisp-test.sh 
>> p0: OPEN video device `/dev/video2'
> 
> After the patch that moved the output preview to be the first one,
> you should probably use /dev/video0 here:

Thanks for the hint, but I've not rebased my tree to those latest couple
of patches yet, the same tree does work on the T101HA with /dev/video2 :)

I think this may be a module load ordering issue, I believe that the
sensor drivers need to be loaded before the atomisp driver itself
and on the T101HA we are hitting this "sweet spot", where as on
the surface I was loading the not yet merged sensor drivers manually,
causing them to be loaded later.

I still need to verify this theory, Tsuchiya can you perhaps confirm 
that the modules must be loaded in this order?

Regards,

Hans