lkml.org 
[lkml]   [2014]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] rtc: Disable EFI rtc for x86
On 11/10/2014 12:37 PM, Austin S Hemmelgarn wrote:
> On 2014-11-10 12:04, Matthew Garrett wrote:
>> On Mon, Nov 10, 2014 at 11:45:06AM -0500, Austin S Hemmelgarn wrote:
>>
>>> I agree, without it you need PC CMOS RTC support to access the RTC
>>> on most systems, which in turn means that you have to enable the CSM
>>> in the EFI firmware, which is annoying cause you can't easily dual
>>> boot windows with secure boot when the CSM is enabled.
>>
>> CMOS RTC support doesn't depend on the CSM.
>>
> That's really interesting, because with it compiled in, I can't boot on
> my EFI based thinkpad laptop without telling EFI to launch the CSM, and
> with it compiled out, I can boot fine without the CSM. I'll have to
> look further into the options I have set in my kernel build, I may have
> changed something else without remembering between booting with and
> without the CSM enabled.
>

It could also be that the non-CSM BIOS somehow remaps the CMOS registers.

-hpa



\
 
 \ /
  Last update: 2014-11-10 22:41    [W:0.115 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site