Planning to write a patch

[Kenneth Adam Miller]

Well, to do that you would have to read the specifications of the
particular hardware. In which case the driver becomes specialized to it-not
useful for anything but your own monitor. But if your monitor provides that
support, then I guess when the ioctl receives a requested change in
brightness you could use that facility of the monitor to retain the setting.

On Wed, Aug 26, 2015 at 2:16 PM, Umair Khan <omerjerk at gmail.com> wrote:

>
>
> On Wed, Aug 26, 2015 at 11:21 PM, Kenneth Adam Miller <
> kennethadammiller at gmail.com> wrote:
>
>> Well, it's probably worth doing for the sake of your learning. However,
>> if you are going to get into the source, I think it's highly likely that
>> you are going to see that the driver provides such a feature to userspace
>> code through means of an ioctl, and in that case, you will probably be able
>> to set the brightness programmatically without ever having to interfere
>> with the driver code itself. So for that matter, the objective doesn't
>> really fit with the complexity you're taking on. If what I'm saying is
>> right, you could easily implement this entirely in userland code by writing
>> a binary and then putting a script in the startup execution so that it
>> calls your binary.
>>
>> If you really want to hack the driver, another way to do it is to just
>> put the brightness setting in the driver's init function, so that when the
>> module is loaded it turns up the brightness. In that case, you *should* get
>> what you want because the driver will be loaded at system boot.
>>
>> On Wed, Aug 26, 2015 at 1:45 PM, Umair Khan <omerjerk at gmail.com> wrote:
>>
>>> Hello everyone,
>>>
>>> I've been thinking of writing a patch a lot lately. But with my level of
>>> knowledge I cannot do something groundbreaking.
>>> One thing which came to my mind is to write a patch related to the
>>> driver which controls the brightness of the display.
>>> What happens now is I lower down the brightness, and when I restart the
>>> laptop, it's back to the highest amount.
>>> I'm using Ubuntu 14.04 LTS on top of Linux Kernel 4.2 rc3+.
>>> I was thinking of writing the current brightness to sysfs and read that
>>> value when the driver is started during the boot.
>>>
>>> So, my question is that is it already implemented in the driver and just
>>> that Ubuntu resets it on every reboot from userspace ?
>>> And if it is not implemented, is it worth implementing ?
>>>
>>> Thanks
>>> Umair
>>> Delhi, India
>>>
>>>
>>>
>>
> I do get this that, most probably this feature would have been provided
> via ioctl. And it is better handled inside the userspace.
> But it'd be just like the hardware is intelligent enough to keep the value
> persistent across reboot. Like the monitor of my PC keeps the brightness,
> and all the different values for that matter, persistent across reboot.
> Userspace can always override this behavior anyways.
>
> Thoughts ?
>
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