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 <[email protected]> wrote: > > > On Wed, Aug 26, 2015 at 11:21 PM, Kenneth Adam Miller < > [email protected]> 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 <[email protected]> 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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