回复: [edk2-devel] [PATCH] PcAtChipsetPkg: Change the flow of PcRtcInit()

["gaoliming" <gaoliming@byosoft.com.cn>]

Zhuoran:
  Ray is the maintainer of PcAtChipsetPkg. Can you collect his feedback on
this change?

Thanks
Liming
> -----邮件原件-----
> 发件人: devel@edk2.groups.io <devel@edk2.groups.io> 代表 Zhuoran Chao
> 发送时间: 2022年4月29日 13:43
> 收件人: devel@edk2.groups.io; Gao, Liming <gaoliming@byosoft.com.cn>
> 抄送: Ni, Ray <ray.ni@intel.com>
> 主题: Re: [edk2-devel] [PATCH] PcAtChipsetPkg: Change the flow of
> PcRtcInit()
> 
> Hi Liming:
> Could you help to give a nudge on the below issue because it is related to
a
> bug fixing of Intel server platform enabling team.
> 
> Thanks
> Zhuoran
> 
> -----Original Message-----
> From: Chao, Zhuoran <zhuoran.chao@intel.com>
> Sent: Monday, April 25, 2022 11:47 PM
> To: devel@edk2.groups.io
> Cc: Chao, Zhuoran <zhuoran.chao@intel.com>; Ni, Ray <ray.ni@intel.com>
> Subject: [PATCH] PcAtChipsetPkg: Change the flow of PcRtcInit()
> 
> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3913
> 
> The original flow of PcRtcInit() is like:
> 1. Guarantee atomic accesses to the RTC time registers and
>    read out the value.
> 2. Program RTC register B. (adopt 12h mode or 24h mode. Current
>    bios code sets RTC to 24h mode by default).
> 3. Then function ConvertRtcTimeToEfiTime converts the RTC time
>    value to their 24h mode by checking the hour format bit
>    (1:24h mode,0:12h mode).
> And here lies the problem: Step3 will fail to adjust the value if Step2
already
> sets RTC to 24h mode. The hour value in 12h mode will not be converted to
its
> 24h mode.
> 
> The solution is to program RTC register B a little later when all the
original RTC
> registers' value is retrieved, adjusted and validated.
> 
> Cc: Ray Ni <ray.ni@intel.com>
> 
> Signed-off-by: Zhuoran Chao <zhuoran.chao@intel.com>
> ---
>  PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
> b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
> index 0fbfa4bcee..ea56a66267 100644
> --- a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
> +++ b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
> @@ -269,13 +269,6 @@ PcRtcInit (
>    Time.Month  = RtcRead (RTC_ADDRESS_MONTH);
>    Time.Year   = RtcRead (RTC_ADDRESS_YEAR);
> 
> -  //
> -  // Set RTC configuration after get original time
> -  // The value of bit AIE should be reserved.
> -  //
> -  RegisterB.Data = FixedPcdGet8 (PcdInitialValueRtcRegisterB) |
> (RegisterB.Data & BIT5);
> -  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
> -
>    //
>    // Release RTC Lock.
>    //
> @@ -330,6 +323,13 @@ PcRtcInit (
>      Time.Daylight   = 0;
>    }
> 
> +  //
> +  // Set RTC configuration after get original time  // The value of bit
> + AIE should be reserved.
> +  //
> +  RegisterB.Data = FixedPcdGet8 (PcdInitialValueRtcRegisterB) |
> + (RegisterB.Data & BIT5);  RtcWrite (RTC_ADDRESS_REGISTER_B,
> + RegisterB.Data);
> +
>    //
>    // Reset time value according to new RTC configuration
>    //
> --
> 2.31.1.windows.1
> 
> 
> 
> 
>