Hi Mika,
On Wed, 5 Feb 2020 18:38:31 +0200, Mika Westerberg wrote:
> On Wed, Feb 05, 2020 at 08:30:48AM -0800, Guenter Roeck wrote:
> > On Wed, Feb 05, 2020 at 05:24:35PM +0200, Mika Westerberg wrote:
> > > You should be able to revert to iTCO_wdt by simply disabling
> > > CONFIG_WDAT_WDT from .config. Then acpi_has_watchdog() returns false
> > > which means that iTCO_wdt is used instead.
> >
> > That may not be possible in a generic distribution.
>
> Right, they would need to build their own kernel. Currently there is no
> way to do that without changing .config.
OK, that's pretty much what I was compl^Wworried about ;-) Would you
consider applying something like the following patch?
From: Jean Delvare <jdelvare@xxxxxxx>
Subject: ACPI / watchdog: Allow disabling WDAT at boot
In case the WDAT interface is broken, give the user the option to
ignore it to let a native driver bind to the watchdog device instead.
Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ++++
drivers/acpi/acpi_watchdog.c | 12 +++++++++++-
2 files changed, 15 insertions(+), 1 deletion(-)
--- linux-5.4.orig/drivers/acpi/acpi_watchdog.c 2020-02-06 15:20:27.187333079 +0100
+++ linux-5.4/drivers/acpi/acpi_watchdog.c 2020-02-06 15:30:08.707408406 +0100
@@ -55,12 +55,14 @@ static bool acpi_watchdog_uses_rtc(const
}
#endif
+static bool acpi_no_watchdog;
+
static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)
{
const struct acpi_table_wdat *wdat = NULL;
acpi_status status;
- if (acpi_disabled)
+ if (acpi_disabled || acpi_no_watchdog)
return NULL;
status = acpi_get_table(ACPI_SIG_WDAT, 0,
@@ -88,6 +90,14 @@ bool acpi_has_watchdog(void)
}
EXPORT_SYMBOL_GPL(acpi_has_watchdog);
+/* ACPI watchdog can be disabled on boot command line */
+static int __init disable_acpi_watchdog(char *str)
+{
+ acpi_no_watchdog = true;
+ return 1;
+}
+__setup("acpi_no_watchdog", disable_acpi_watchdog);
+
void __init acpi_watchdog_init(void)
{
const struct acpi_wdat_entry *entries;
--- linux-5.4.orig/Documentation/admin-guide/kernel-parameters.txt 2020-02-06 15:20:27.187333079 +0100
+++ linux-5.4/Documentation/admin-guide/kernel-parameters.txt 2020-02-06 15:31:16.614155680 +0100
@@ -136,6 +136,10 @@
dynamic table installation which will install SSDT
tables to /sys/firmware/acpi/tables/dynamic.
+ acpi_no_watchdog [HW,ACPI,WDT]
+ Ignore the ACPI-based watchdog interface (WDAT) and let
+ a native driver control the watchdog device instead.
+
acpi_rsdp= [ACPI,EFI,KEXEC]
Pass the RSDP address to the kernel, mostly used
on machines running EFI runtime service to boot the
Thanks,
--
Jean Delvare
SUSE L3 Support
