Messages in this thread | | | Date | Thu, 21 Apr 2011 23:12:50 -0400 | From | Youquan Song <> | Subject | Re: [PATCH v4 1/2] apic: Fix error interrupt report at all APs |
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> I don't disagree with this change, but unfortunately the changelog is in > absolutely unreadable English. Please fix it or find someone who can fix it for > you. > > I decoded and fixed the changelog of the 2/2 patch of your series so no need to > do it for that patch.
Thanks a lot Ingo!
Here is the fixed changelog for 1/2 patch :Fix error interrupt report at all APs
This patch fixes a bug reported from customer, who found many unreasonable error interrupts reported on all APs during the system boot stage.
According to Chapter 10 of Intel Software Developer Manual Volume 3A, Local APIC may signal an illegal vector error when an LVT entry is set as an illegal vector value (0~15) under FIXED delivery mode (bits 8-11 is 0), regardless of whether the mask bit is set or an interrupt actually happen. These errors are seen as error interrupts.
The initial value of thermal LVT entries on all APs always reads 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI sequence to them and LVT registers are reset to 0s except for the mask bits which are set to 1s when APs receive INIT IPI. When BIOS take over the thermal throttling interrupt, LVT thermal deliver mode should be SMI and it is required to restore AP's LVT thermal monitor register.
This issue happens when BIOS do not take over thermal throttling interrupt, AP's LVT thermal monitor register will be restored to 0x10000 which means vector 0 and fixed deliver mode, so all APs will signal illegal vector error interrupt. This patch check if interrupt delivery mode is not fixed mode before restore AP's LVT thermal monitor register.
-Youquan
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