Re: [LAU] NOW - UEFI

On 08/29/2014 07:23 PM, dale wrote:
> 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...

ACPI handles power-related things. It (or something proprietary) may
also handle things like the FN key functions on laptops, which include
brightening, dimming, switching display outputs, on/off/volume of built
in audio hardware, enabling touchpad, wireless, stuffs like that. Well,
actually, keyboard driver has to first recognize those keystrokes, then
the system has to carry out the correct command - which might require
triggering an ACPI event?

-- 
David W. Jones
gnome@email-addr-hidden
authenticity, honesty, community
http://dancingtreefrog.com
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user