[coreboot] Patch set updated: f2674cc i82801gx: read RTC status register to prevent IRQ storm

[Sven Schnelle (svens@stackframe.org)]

Sven Schnelle (svens at stackframe.org) just uploaded a new patch set to gerrit, which you can find at
http://review.coreboot.org/67

-gerrit

commit f2674cc3d7e90ed01af8449f8786aa7f42cb84b8
Author: Sven Schnelle <svens at stackframe.org>
Date:   Wed Jun 29 15:05:28 2011 +0200

    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 at stackframe.org>
---
 src/southbridge/intel/i82801gx/smihandler.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/src/southbridge/intel/i82801gx/smihandler.c b/src/southbridge/intel/i82801gx/smihandler.c
index 434bfeb..48375e4 100644
--- a/src/southbridge/intel/i82801gx/smihandler.c
+++ b/src/southbridge/intel/i82801gx/smihandler.c
@@ -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)