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i82801gx: read RTC status register to prevent IRQ storm 

My Thinkpad appeared dead. After investigation, it turned out
that the RTC Alarm was triggering an RTC PM1 SMI, but the SMI
handler didn't read the status register, so it was triggered again.

This is a really nasty situation, as it means you have to dissemble
your Notebook just to unplug the RTC battery.

Change-Id: I5ac611e8a72deb5f38c86486dbe0693804935723
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-on: http://review.coreboot.org/67
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
This commit is contained in:
Sven Schnelle 2011-06-29 15:05:28 +02:00 committed by Patrick Georgi
parent 55bf2e49d6
commit 811787abd5
1 changed files with 8 additions and 0 deletions
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8
src/southbridge/intel/i82801gx/smihandler.c
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@ -26,6 +26,7 @@
#include <cpu/x86/cache.h>
#include <cpu/x86/smm.h>
#include <device/pci_def.h>
#include <pc80/mc146818rtc.h>
#include "i82801gx.h"
/* I945 */
@ -410,6 +411,7 @@ static void southbridge_smi_apmc(unsigned int node, smm_state_save_area_t *state
static void southbridge_smi_pm1(unsigned int node, smm_state_save_area_t *state_save)
{
u16 pm1_sts;
volatile u8 cmos_status;
pm1_sts = reset_pm1_status();
dump_pm1_status(pm1_sts);
@ -423,6 +425,12 @@ static void southbridge_smi_pm1(unsigned int node, smm_state_save_area_t *state_
reg32 = (7 << 10) | (1 << 13);
outl(reg32, pmbase + PM1_CNT);
}
if (pm1_sts & RTC_STS) {
/* read RTC status register to disable the interrupt */
cmos_status = cmos_read(RTC_REG_C);
printk(BIOS_DEBUG, "RTC IRQ status: %02X\n", cmos_status);
}
}
static void southbridge_smi_gpe0(unsigned int node, smm_state_save_area_t *state_save)