On Sun, May 30, 2021 at 01:24:23PM +0200, Jan Kiszka wrote: > From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> > > This was already attempted to fix via 1fccb73011ea: If the BIOS did not > enable TCO SMIs, the timer definitely needs to trigger twice in order to > cause a reboot. If TCO SMIs are on, as well as SMIs in general, we can > continue to assume that the BIOS will perform a reboot on the first > timeout. > > QEMU with its ICH9 and related BIOS falls into the former category, > currently taking twice the configured timeout in order to reboot the > machine. For iTCO version that fall under turn_SMI_watchdog_clear_off, > this is also true and was currently only addressed for v1, irrespective > of the turn_SMI_watchdog_clear_off value. > > Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> > --- > > Changes in v2: > - consider GBL_SMI_EN as well > > drivers/watchdog/iTCO_wdt.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c > index bf31d7b67a69..3f1324871cfd 100644 > --- a/drivers/watchdog/iTCO_wdt.c > +++ b/drivers/watchdog/iTCO_wdt.c > @@ -71,6 +71,8 @@ > #define TCOBASE(p) ((p)->tco_res->start) > /* SMI Control and Enable Register */ > #define SMI_EN(p) ((p)->smi_res->start) > +#define TCO_EN (1 << 13) > +#define GBL_SMI_EN (1 << 0) > > #define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */ > #define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/ > @@ -355,8 +357,12 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t) > > tmrval = seconds_to_ticks(p, t); > > - /* For TCO v1 the timer counts down twice before rebooting */ > - if (p->iTCO_version == 1) > + /* > + * If TCO SMIs are off, the timer counts down twice before rebooting. > + * Otherwise, the BIOS generally reboots when the SMI triggers. > + */ > + if (p->smi_res && > + (SMI_EN(p) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN)) > tmrval /= 2; > > /* from the specs: */ > @@ -521,7 +527,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev) > * Disables TCO logic generating an SMI# > */ > val32 = inl(SMI_EN(p)); > - val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */ > + val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */ > outl(val32, SMI_EN(p)); > } > > -- > 2.26.2
