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. ConvertRtcTimeToEfiTime is modified to be more robust. Cc: Ray Ni <ray...@intel.com> Signed-off-by: Zhuoran Chao <zhuoran.c...@intel.com> --- .../PcatRealTimeClockRuntimeDxe/PcRtc.c | 38 +++++++++++++------ 1 file changed, 27 insertions(+), 11 deletions(-) diff --git a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c index 0fbfa4bcee..dbce7c217c 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 // @@ -995,10 +995,26 @@ ConvertRtcTimeToEfiTime ( BOOLEAN IsPM; UINT8 Century; - if ((Time->Hour & 0x80) != 0) { - IsPM = TRUE; - } else { - IsPM = FALSE; + // Check 24-hour format situation + if (RegisterB.Bits.Mil == 1) { + if (RegisterB.Bits.Dm == 0) { + if (Time->Hour > 0x23) { + return EFI_INVALID_PARAMETER; + } + } else { + if (Time->Hour > 0x17) { + return EFI_INVALID_PARAMETER; + } + } + } + + // IsPM only makes sense for 12-hour format. + if (RegisterB.Bits.Mil == 0) { + if ((Time->Hour & 0x80) != 0) { + IsPM = TRUE; + } else { + IsPM = FALSE; + } } Time->Hour = (UINT8)(Time->Hour & 0x7f); -- 2.31.1.windows.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#89569): https://edk2.groups.io/g/devel/message/89569 Mute This Topic: https://groups.io/mt/90947516/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-