Planning to write a patch

[Umair Khan]

You got a little bit wrong.
I just used monitor to give an example that I have a separate PC whose
monitor provides this feature.
I actually want to implement it for the display of my laptop.
I'll just do it for my driver though. I guess it's already hardware
specific in the first place.

On Thu 27 Aug, 2015 12:00 am Kenneth Adam Miller <
kennethadammiller at gmail.com> wrote:

> 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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