Re: Question regarding CMOS regions.

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

Younas,
Why are you still working on CMOS in now UEFI world?
Detailed answer is in below.

Thanks/Ray

> -----Original Message-----
> From: edk2-devel <edk2-devel-bounces@lists.01.org> On Behalf Of
> MohammadYounasKhan.P@Dell.com
> Sent: Thursday, August 16, 2018 12:44 PM
> To: edk2-devel@lists.01.org
> Subject: Re: [edk2] Question regarding CMOS regions.
> 
> Hi Guys,
> 
> Please help to reply to my below queries.
> 
> Thank you,
> Younas.
> 
> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Pathan, MohammadYounasKhan
> Sent: Tuesday, August 14, 2018 9:17 AM
> To: edk2-devel@lists.01.org
> Subject: [edk2] FW: Question regarding CMOS regions.
> 
> Hi All,
> 
> As we know CMOS data can be 128 or 256 bytes. CMOS lower 128 bytes are
> stored in IO ports 0x70-0x71 whereas CMOS upper 128 bytes are stored using IO
> ports 0x72-0x73.
> 
>   1.  How to know that the system has 128bytes of CMOS or 256 bytes of CMOS
> region?
You could read the data to know whether high 128 bytes are valid or not.

>   2.  Is there any CMOS location which represents CMOS upper region is exists or
> valid or any other mechanism for it?
Refer to #1.
>   3.  Are we replicating lower 128 bytes to upper 128 bytes in CMOS location
> 0x70-0x71 (or 0x72-0x73)? If yes, Why are we doing that?
It depends on BIOS implementation. I don't see any bios is duplicating the contents.
> 
> Thank you,
> Younas.
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