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-rw-r--r--0003-ACPI-watchdog-Prefer-iTCO_wdt-always-when-WDAT-table.patch127
1 files changed, 127 insertions, 0 deletions
diff --git a/0003-ACPI-watchdog-Prefer-iTCO_wdt-always-when-WDAT-table.patch b/0003-ACPI-watchdog-Prefer-iTCO_wdt-always-when-WDAT-table.patch
new file mode 100644
index 00000000000..5c029d37f3e
--- /dev/null
+++ b/0003-ACPI-watchdog-Prefer-iTCO_wdt-always-when-WDAT-table.patch
@@ -0,0 +1,127 @@
+From 7bb20c91fc051b79bcd774030b6c900c29e325d4 Mon Sep 17 00:00:00 2001
+From: Mika Westerberg <mika.westerberg@linux.intel.com>
+Date: Tue, 22 May 2018 14:16:50 +0300
+Subject: [PATCH 3/5] ACPI / watchdog: Prefer iTCO_wdt always when WDAT table
+ uses RTC SRAM
+
+After we added quirk for Lenovo Z50-70 it turns out there are at least
+two more systems where WDAT table includes instructions accessing RTC
+SRAM. Instead of quirking each system separately, look for such
+instructions in the table and automatically prefer iTCO_wdt if found.
+
+Link: https://bugzilla.kernel.org/show_bug.cgi?id=199033
+Reported-by: Arnold Guy <aurnoldg@gmail.com>
+Reported-by: Alois Nespor <nespor@fssp.cz>
+Reported-by: Yury Pakin <zxwarior@gmail.com>
+Reported-by: Ihor Chyhin <ihorchyhin@ukr.net>
+Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
+Acked-by: Guenter Roeck <linux@roeck-us.net>
+---
+ drivers/acpi/acpi_watchdog.c | 72 ++++++++++++++++++++++--------------
+ 1 file changed, 45 insertions(+), 27 deletions(-)
+
+diff --git a/drivers/acpi/acpi_watchdog.c b/drivers/acpi/acpi_watchdog.c
+index 4bde16fb97d8..95600309ce42 100644
+--- a/drivers/acpi/acpi_watchdog.c
++++ b/drivers/acpi/acpi_watchdog.c
+@@ -12,35 +12,51 @@
+ #define pr_fmt(fmt) "ACPI: watchdog: " fmt
+
+ #include <linux/acpi.h>
+-#include <linux/dmi.h>
+ #include <linux/ioport.h>
+ #include <linux/platform_device.h>
+
+ #include "internal.h"
+
+-static const struct dmi_system_id acpi_watchdog_skip[] = {
+- {
+- /*
+- * On Lenovo Z50-70 there are two issues with the WDAT
+- * table. First some of the instructions use RTC SRAM
+- * to store persistent information. This does not work well
+- * with Linux RTC driver. Second, more important thing is
+- * that the instructions do not actually reset the system.
+- *
+- * On this particular system iTCO_wdt seems to work just
+- * fine so we prefer that over WDAT for now.
+- *
+- * See also https://bugzilla.kernel.org/show_bug.cgi?id=199033.
+- */
+- .ident = "Lenovo Z50-70",
+- .matches = {
+- DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+- DMI_MATCH(DMI_PRODUCT_NAME, "20354"),
+- DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo Z50-70"),
+- },
+- },
+- {}
+-};
++#ifdef CONFIG_RTC_MC146818_LIB
++#include <linux/mc146818rtc.h>
++
++/*
++ * There are several systems where the WDAT table is accessing RTC SRAM to
++ * store persistent information. This does not work well with the Linux RTC
++ * driver so on those systems we skip WDAT driver and prefer iTCO_wdt
++ * instead.
++ *
++ * See also https://bugzilla.kernel.org/show_bug.cgi?id=199033.
++ */
++static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
++{
++ const struct acpi_wdat_entry *entries;
++ int i;
++
++ entries = (struct acpi_wdat_entry *)(wdat + 1);
++ for (i = 0; i < wdat->entries; i++) {
++ const struct acpi_generic_address *gas;
++
++ gas = &entries[i].register_region;
++ if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
++ switch (gas->address) {
++ case RTC_PORT(0):
++ case RTC_PORT(1):
++ case RTC_PORT(2):
++ case RTC_PORT(3):
++ return true;
++ }
++ }
++ }
++
++ return false;
++}
++#else
++static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
++{
++ return false;
++}
++#endif
+
+ static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)
+ {
+@@ -50,9 +66,6 @@ static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)
+ if (acpi_disabled)
+ return NULL;
+
+- if (dmi_check_system(acpi_watchdog_skip))
+- return NULL;
+-
+ status = acpi_get_table(ACPI_SIG_WDAT, 0,
+ (struct acpi_table_header **)&wdat);
+ if (ACPI_FAILURE(status)) {
+@@ -60,6 +73,11 @@ static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)
+ return NULL;
+ }
+
++ if (acpi_watchdog_uses_rtc(wdat)) {
++ pr_info("Skipping WDAT on this system because it uses RTC SRAM\n");
++ return NULL;
++ }
++
+ return wdat;
+ }
+
+--
+2.18.0
+