Ray: The problem is that PcdFSBClock is configured as Dynamic on OVMF. Anthony: Have you any suggestion for this problem? Thanks Liming 发件人: devel@edk2.groups.io 代表 ray_linn@hotmail.com 发送时间: 2022年7月7日 12:13 收件人: Anthony PERARD ; devel@edk2.groups.io 主题: Re: [edk2-devel] [PATCH v2 2/7] MdePkg: Allow PcdFSBClock to by Dynamic On Thu, Mar 25, 2021 at 11:47 PM, Anthony PERARD wrote: - ## This value is used to configure X86 Processor FSB clock. - # @Prompt FSB Clock. - gEfiMdePkgTokenSpaceGuid.PcdFSBClock|200000000|UINT32|0x0000000c hi, Sir This change caused the OVMF failed to load in QEMU when compiled with "SOURCE_DEBUG_ENABLE" as True. the verbose message of QEMU shows: ASSERT [SecMain] d:\myedk2\edk2\MdePkg\Library\BasePcdLibNull\PcdLib.c(95): ((BOOLEAN)(0==1)) The failure point is PcdGet32 (PcdFSBClock) of debugtimer.c, I rolled back above change, then issue disappeared.