HID Monitor Driver Advice

Mark Bolhuis mark at bolhuis.dev
Thu Apr 15 15:27:58 EDT 2021

On 15/04/2021 16:44, Greg KH wrote:
> Why do you need a kernel driver at all?  Why not just use the userspace
> hid access and control stuff that way from an application? >
> If you write your own driver, you can do that from within the driver I
> think.  But again, what's wrong with userspace?
> thanks,
> greg k-h

A couple reasons. These might be misplaced since I'm very new to kernel 

I would like to create very simple user space scripts and programs on 
top of it. I'd like to change settings with nothing more than an `echo 
200 > brightness`. Something has to keep track of an internal state, 
which I'd rather not happen in userspace apps, so I decided on a driver.

I'd like to eventually use linux/backlight.h to control brightness 
which, correct me if I'm wrong, has to be used from a kernel driver. Or 
is this an unsuitable use case?

I assume you are referring to uhid? I've got no issue using it but my 
initial impressions led me to think it wouldn't have been as elegant. 
Again I could be wrong. I'll do some more research on it.


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