[LAU] NOW - UEFI

dale dj_kaza at hotmail.com
Sat Aug 30 05:23:33 UTC 2014


On Fri, 2014-08-29 at 09:45 -0700, Len Ovens wrote:
> On Fri, 29 Aug 2014, dale wrote:
> 
> > This has caused various headaches I have kind learned to live with. Main
> > one being relating to screen brightness. If I set a low default screen
> > brightness in Windows then it seems to change the range of brightness
> > Linux can display. This was even more noticable when running LiveUSB
> > distros! I actually couldn't get the screen bright enough to see what I
> > was doing without setting the level within Windows bright again!
> 
> Is there a setting in regular bios for screen brightness? EFI my leave 
> some variables around that the OS can continue to manipulat after boot... 
> wonderful :P
> 
No and I've looked again and again thinking it must be settable
elsewhere if it can be set from the Lenovo software/Windows and affect
all booted OSes.

> > Then I read (or skimmed) this yesterday and feel even more confused.
> > https://wiki.archlinux.org/index.php/UEFI
> 
> I see what you mean, every time I thought I was getting somewhere, I got 
> sent to yet another page. The most I got out of it was that EFI is intel's 
> answer to grub but with more control of the firware settings at the same 
> time. The old bios included calls to access some of the HW, but no one 
> used them as they were not muti-task/user friendly. It appears EFI does 
> the same thing and windows uses it and Linux does not know how to access 
> at least part of it. (or windows sets up its own calls within it)
> 
> 
> > But I am starting to think I should try enabling it with a Linux
> > install. Especially as I plan to completely banish Windows from the
> > computer now... But I thought I would ask what more experienced Linux
> > users have to say about UEFI mode vs BIOS/Legacy mode.
> 
> You will get some I don't doubt... it may be hard to tell the truth from 
> FUD  ;)   EFI and Linux are still relatively new (3.10ish) and complaints 
> found in one kernel version may no longer be true.
> 
> --
> Len Ovens
> www.ovenwerks.net
> 

I guess it must tie into ACPI somehow. Or would that be a silly
assumption? I believe ACPI controls hardware functions, including screen
brightness and fan controllers, while the system is running. Or am I
confused? I know on the rare occasions I've had a crash there have been
lots of ACPI Unknown (or similar) messages in my log! Did mean to look
into it further at some point...



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