Currently I am using Linux 3.8.0-27-generic kernel on my Samsung laptop. I replaced grub configuration file with the following text to make backlight control work:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"

I do not know if doing this causes a regression. If not, why is this not being included in the never version of kernels? There are not millions of computer manufacturers and at least this could be hardcoded, right?

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    Linux isn't meant to cover everyone all of the time, and is often used on old computers that don't always have new bells and whistles, you got it to work in the end, without too much time or effort, so why complain? – Eric Jul 30 '13 at 16:25
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    Also remember that the vast majority of Linuxes run on servers that do not need this feature. – terdon Jul 30 '13 at 16:41
  • @Eric there is no complaint of course. The question was why this is not by default if there is no regression? – user1754665 Jul 30 '13 at 17:07

Well it sure can be hardcoded. Get the sources, configure on your own, and set the appropriate value for backlight. I haven't tinkered much with backlight modules, however. There might be some value you could pass on module loading or as a boot param different from acpi_backlight.

You should know that every linux distribution, although their maintaners do attempt to cover all thinkable hardware, has to make a trade-off on the size of the compiled libraries, their inclusion in the kernel (to not make it monolithic with huge run-time overhead) and hardware support. The more hardware you wish to support, the more overhead you get. The less overhead you project, the less hardware will be supported. On modern systems this is negligible, however.

If you do your own .config, you'll be all set, and maybe you won't have any more troubles with backlight. I just don't know much of your particular set up.

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