4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 5a802a7a285c8877ca872e44eeb0f06afcb5212f ]
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 Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 ca2724893541..396e358c2cee 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; }