Re: [PATCH 0/1] platform/x86/tuxedo: Add virtual LampArray for TUXEDO NB04

[Werner Sembach <wse@tuxedocomputers.com>]

Hi Benjamin,

Am 27.09.24 um 18:08 schrieb Benjamin Tissoires:
> On Sep 26 2024, Werner Sembach wrote:
>> Hi,
>> took some time but now a first working draft of the suggested new way of
>> handling per-key RGB keyboard backlights is finished. See:
>> https://lore.kernel.org/all/1fb08a74-62c7-4d0c-ba5d-648e23082dcb@tuxedocomputers.com/
>> First time for me sending a whole new driver to the LKML, so please excuse
>> mistakes I might have made.
>>
>> Known bugs:
>> - The device has a lightbar which is currently not implemented and
>>    therefore stuck to blue once the first backlight control command is send.
>>
>> What is still missing:
>> - The leds fallback
>> - Lightbar control
>>
>> Some general noob questions:
>>
>> Initially I though it would be nice to have 2 modules, one jsut being the
>> wmi initialization and utility stuff and one just being the backlight logic
>> stuff, being loaded automatically via module_alias, but that would still
>> require me to create the virtual hid device during the wmi_ab probe, and
>> that already needs the ll_driver, so i guess I have to do it statically
>> like i did now?
>> Or in other words: I would have liked to have a module dependency graph
>> like this:
>>      tuxedo_nb04_lamp_array depends on tuxedo_nb04_platform (combining *_wmi_init and *_wmi_utility)
>> but if i currently split it into modules i would get this:
>>      tuxedo_nb04_wmi_ab_init dpends on tuxedo_nb04_wmi_ab_lamp_array depends on tuxedo_nb04_wmi_utility
> On more general question to you: how much confident are you about your
> LampArray implementation?
>
> If you still need to add/fix stuff in it, I would advise you to have a
> simple HID device, with bare minimum functionality, and then add the
> LampArray functionality on top through HID-BPF. This way you can fix
> LampArray out of band with the kernel, while having a more stable kernel
> module. This should be possible with v6.11+.
>
> Another solution is to still have your wmi-to-hid module, and then a
> HID kernel module in drivers/hid that supports LampArray.
>
> But I would strongly suggest while you are figuring out the userspace
> part to stick to HID-BPF, and then once you are happy we can move to a
> full kernel module.

I don't expect this patch to get merged right away, but like i wrote, 
wanted to collect some feedback on it to already start refining it.

With this driver now functional I have something to build and test 
userspace against while waiting on the feedback and the undoubtly 
following discussion of details to get it right ^^.

Until now I only tested with a very simple, self built command line 
binary, looping some patterns. My next step is to try the work in 
progress implementetion for LampArray in OpenRGB: 
https://gitlab.com/CalcProgrammer1/OpenRGB/-/merge_requests/2348

Regards,

Werner

>
> Cheers,
> Benjamin
>
>> Currently after creating the virtual hdev in the wmi init probe function I
>> have to keep track of it and manually destroy it during the wmi init
>> remove. Can this be automated devm_kzalloc-style?
>>
>> Kind regards,
>> Werner Sembach
>>
>>