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Date:   Sun, 3 Dec 2023 16:44:17 +0100
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Subject: Re: PROBLEM: asus_nb_wmi sends KEY_BRIGHTNESSDOWN on pressing CAPS
 Lock and PrntScrn on Zenbook S 13 UX5304VA
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From:   Hans de Goede <hdegoede@redhat.com>
To:     Juri Vitali <juri@dividebyzero.it>, James John <me@donjajo.com>,
        Corentin Chary <corentin.chary@gmail.com>,
        =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,
        Mark Gross <markgross@kernel.org>
Cc:     platform-driver-x86@vger.kernel.org,
        acpi4asus-user@lists.sourceforge.net, linux-kernel@vger.kernel.org
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Hi Juri,

On 11/25/23 15:25, Hans de Goede wrote:
> Hi Juri,
> 
> On 11/24/23 16:54, Juri Vitali wrote:
>> Hi,
>> Unfortunately those patches have broken the backlight reporting on older 
>> laptops, which do rely on the old mechanism.
> 
> Thank you for reporting this and sorry about the regression.
> 
> And thank you for writing a good bug report with as much info
> included as possible, that is much appreciated.
> 
>> For instance, on my Asus UX32A/VD when pressing the backlight up/down button 
>> the backlight changes accordingly,
> 
> Ok, so the embedded-controller (EC) is adjusting the brightness
> itself in reaction to the key presses, which means that
> the old behavior of sending KEY_BRIGHTNESSDOWN / 
> KEY_BRIGHTNESSUP was not really correct because that will
> cause e.g. GNOME to then increase the brightness itself
> which means that if the new brightness is correctly reflected
> when reading it GNOME may increase the brightness an
> additional step on top of the step it has already been
> increased by the EC itself.
> 
> Which makes me wonder how to properly solve this,
> so I have a bunch of questions:
> 
> 1. What desktop environment are you using ?
> 
> 2. Assuming you are using GNOME (for now) I guess that with older
> kernels you got an on-screen-display (OSD) notification about
> the brightness changing? Do you notice any difference in how
> many total steps you have going from min to max with older
> kernels vs the new kernel ?  If the double increase problem
> happens I guess you only get 5 brightness levels in GNOME /
> 4 steps from going from minimal to maximum ?
> 
> 
> Note below questions should all be answered with the new kernel
> with the unknown key messages in dmesg.
> 
> 
> 3. Can you do:
> 
> ls /sys/class/backlight
> 
> And let me know the output, I wonder what method is being
> used to control backlight on your machine.
> 
> 4. Can you do:
> 
> cat /sys/class/backlight/$name/max_brightness
> 
> What does this say?
> 
> With $name being the name from 3.
> 
> 5. Can you do:
> 
> cat /sys/class/backlight/$name/brightness
> 
> And then change the brightness using the keys, and then
> again do:
> 
> cat /sys/class/backlight/$name/brightness
> 
> What are the values shown before / after changing it ?
> 
> 6. Can you repeat 5 but then do:
> 
> cat /sys/class/backlight/$name/actual_brightness
> 
> 7. Can you run:
> 
> sudo acpidump -o acpidump.txt
> 
> And then email me the generated acpidump.txt file
> in a private email ?

I guess you have not been able to make some time to answer
the above questions yet.

Any chance you can make some time to gather this info soon ?

Regards,

Hans