From: Yong Wang Date: Tue, 10 Nov 2009 01:38:24 +0000 (+0800) Subject: x86: Under BIOS control, restore AP's APIC_LVTTHMR to the BSP value X-Git-Tag: v2.6.33-rc1~399^2~1^2~4 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a2202aa29289db64ca7988b12343158b67b27f10;p=pandora-kernel.git x86: Under BIOS control, restore AP's APIC_LVTTHMR to the BSP value On platforms where the BIOS handles the thermal monitor interrupt, APIC_LVTTHMR on each logical CPU is programmed to generate a SMI and OS must not touch it. Unfortunately AP bringup sequence using INIT-SIPI-SIPI clears all the LVT entries except the mask bit. Essentially this results in all LVT entries including the thermal monitoring interrupt set to masked (clearing the bios programmed value for APIC_LVTTHMR). And this leads to kernel take over the thermal monitoring interrupt on AP's but not on BSP (leaving the bios programmed value only on BSP). As a result of this, we have seen system hangs when the thermal monitoring interrupt is generated. Fix this by reading the initial value of thermal LVT entry on BSP and if bios has taken over the control, then program the same value on all AP's and leave the thermal monitoring interrupt control on all the logical cpu's to the bios. Signed-off-by: Yong Wang Reviewed-by: Suresh Siddha Cc: Borislav Petkov Cc: Arjan van de Ven LKML-Reference: <20091110013824.GA24940@ywang-moblin2.bj.intel.com> Signed-off-by: Ingo Molnar Cc: stable@kernel.org --- Reading git-diff-tree failed