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authorWim Van Sebroeck <wim@iguana.be>2009-06-08 17:41:51 +0000
committerWim Van Sebroeck <wim@iguana.be>2009-06-18 07:31:58 +0000
commit55e8ddecec6a9dbe35a99d03cc4189fd7c56e600 (patch)
treeb0b13894e0054481601bc173f73facbc0c24fa23 /drivers/watchdog
parentde8cd9a3067e25a860c225f794e6b249b73aa6b1 (diff)
[WATCHDOG] iTCO_wdt: Fix ICH7+ reboot issue.
Bugzilla: 9868 & 10195. There seems to be a bug into the SMM code that handles TCO Timeout SMI. Andriy Gapon found that the code on his DG33TL system does the following: > The handler is quite simple - it tests value in TCO1_CNT against 0x800, i.e. > checks TCO_TMR_HLT. If the bit is set the handler goes into an infinite loop, > apparently to allow the second timeout and reboot. Otherwise it simply clears > TIMEOUT bit in TCO1_STS and that's it. > So the logic seems to be reversed, because it is hard to see how TIMEOUT can > get set to 1 and SMI generated when TCO_TMR_HLT is set (other than a > transitional effect). The only trick we have is to bypass the SMM code by turning of the generation of the SMI#. The trick can only be enabled by setting the vendorsupport module parameter to 911. This trick doesn't work well on laptop's. Note: this is a dirty hack. Please handle with care. The only real fix is that the bug in the SMM bios code get's fixed. Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog')
-rw-r--r--drivers/watchdog/iTCO_vendor_support.c82
1 files changed, 76 insertions, 6 deletions
diff --git a/drivers/watchdog/iTCO_vendor_support.c b/drivers/watchdog/iTCO_vendor_support.c
index 843ef626bc5..5133bca5ccb 100644
--- a/drivers/watchdog/iTCO_vendor_support.c
+++ b/drivers/watchdog/iTCO_vendor_support.c
@@ -19,7 +19,7 @@
/* Module and version information */
#define DRV_NAME "iTCO_vendor_support"
-#define DRV_VERSION "1.03"
+#define DRV_VERSION "1.04"
#define PFX DRV_NAME ": "
/* Includes */
@@ -44,11 +44,14 @@
#define SUPERMICRO_OLD_BOARD 1
/* SuperMicro Pentium 4 / Xeon 4 / EMT64T Era Systems */
#define SUPERMICRO_NEW_BOARD 2
+/* Broken BIOS */
+#define BROKEN_BIOS 911
static int vendorsupport;
module_param(vendorsupport, int, 0);
MODULE_PARM_DESC(vendorsupport, "iTCO vendor specific support mode, default="
- "0 (none), 1=SuperMicro Pent3, 2=SuperMicro Pent4+");
+ "0 (none), 1=SuperMicro Pent3, 2=SuperMicro Pent4+, "
+ "911=Broken SMI BIOS");
/*
* Vendor Specific Support
@@ -243,25 +246,92 @@ static void supermicro_new_pre_set_heartbeat(unsigned int heartbeat)
}
/*
+ * Vendor Support: 911
+ * Board: Some Intel ICHx based motherboards
+ * iTCO chipset: ICH7+
+ *
+ * Some Intel motherboards have a broken BIOS implementation: i.e.
+ * the SMI handler clear's the TIMEOUT bit in the TC01_STS register
+ * and does not reload the time. Thus the TCO watchdog does not reboot
+ * the system.
+ *
+ * These are the conclusions of Andriy Gapon <avg@icyb.net.ua> after
+ * debugging: the SMI handler is quite simple - it tests value in
+ * TCO1_CNT against 0x800, i.e. checks TCO_TMR_HLT. If the bit is set
+ * the handler goes into an infinite loop, apparently to allow the
+ * second timeout and reboot. Otherwise it simply clears TIMEOUT bit
+ * in TCO1_STS and that's it.
+ * So the logic seems to be reversed, because it is hard to see how
+ * TIMEOUT can get set to 1 and SMI generated when TCO_TMR_HLT is set
+ * (other than a transitional effect).
+ *
+ * The only fix found to get the motherboard(s) to reboot is to put
+ * the glb_smi_en bit to 0. This is a dirty hack that bypasses the
+ * broken code by disabling Global SMI.
+ *
+ * WARNING: globally disabling SMI could possibly lead to dramatic
+ * problems, especially on laptops! I.e. various ACPI things where
+ * SMI is used for communication between OS and firmware.
+ *
+ * Don't use this fix if you don't need to!!!
+ */
+
+static void broken_bios_start(unsigned long acpibase)
+{
+ unsigned long val32;
+
+ val32 = inl(SMI_EN);
+ /* Bit 13: TCO_EN -> 0 = Disables TCO logic generating an SMI#
+ Bit 0: GBL_SMI_EN -> 0 = No SMI# will be generated by ICH. */
+ val32 &= 0xffffdffe;
+ outl(val32, SMI_EN);
+}
+
+static void broken_bios_stop(unsigned long acpibase)
+{
+ unsigned long val32;
+
+ val32 = inl(SMI_EN);
+ /* Bit 13: TCO_EN -> 1 = Enables TCO logic generating an SMI#
+ Bit 0: GBL_SMI_EN -> 1 = Turn global SMI on again. */
+ val32 |= 0x00002001;
+ outl(val32, SMI_EN);
+}
+
+/*
* Generic Support Functions
*/
void iTCO_vendor_pre_start(unsigned long acpibase,
unsigned int heartbeat)
{
- if (vendorsupport == SUPERMICRO_OLD_BOARD)
+ switch (vendorsupport) {
+ case SUPERMICRO_OLD_BOARD:
supermicro_old_pre_start(acpibase);
- else if (vendorsupport == SUPERMICRO_NEW_BOARD)
+ break;
+ case SUPERMICRO_NEW_BOARD:
supermicro_new_pre_start(heartbeat);
+ break;
+ case BROKEN_BIOS:
+ broken_bios_start(acpibase);
+ break;
+ }
}
EXPORT_SYMBOL(iTCO_vendor_pre_start);
void iTCO_vendor_pre_stop(unsigned long acpibase)
{
- if (vendorsupport == SUPERMICRO_OLD_BOARD)
+ switch (vendorsupport) {
+ case SUPERMICRO_OLD_BOARD:
supermicro_old_pre_stop(acpibase);
- else if (vendorsupport == SUPERMICRO_NEW_BOARD)
+ break;
+ case SUPERMICRO_NEW_BOARD:
supermicro_new_pre_stop();
+ break;
+ case BROKEN_BIOS:
+ broken_bios_stop(acpibase);
+ break;
+ }
}
EXPORT_SYMBOL(iTCO_vendor_pre_stop);