| Message ID | 20190106082103.evfgarznrskd4oxh@dcvr |
|---|---|
| State | Accepted |
| Headers | show |
| Series | rtc: cmos: ignore bogus century byte | expand |
On 06/01/2019 08:21:03+0000, Eric Wong wrote: > Older versions of Libreboot and Coreboot had an invalid value > (`3' in my case) in the century byte affecting the GM45 in > the Thinkpad X200. Not everybody's updated their firmwares, > and Linux <= 4.2 was able to read the RTC without problems, > so workaround this by ignoring invalid values. > Does this mean that it is set to an invalid value and that in is not getting updated properly in mc146818_set_time? > Fixes: 3c217e51d8a272b9 ("rtc: cmos: century support") > > Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> > Cc: Alessandro Zummo <a.zummo@towertech.it> > Cc: Sylvain Chouleur <sylvain.chouleur@intel.com> > Cc: Patrick McDermott <patrick.mcdermott@libiquity.com> > Cc: linux-rtc@vger.kernel.org > Signed-off-by: Eric Wong <e@80x24.org> > --- > drivers/rtc/rtc-mc146818-lib.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c > index 2f1772a358ca..18a6f15e313d 100644 > --- a/drivers/rtc/rtc-mc146818-lib.c > +++ b/drivers/rtc/rtc-mc146818-lib.c > @@ -82,7 +82,7 @@ unsigned int mc146818_get_time(struct rtc_time *time) > time->tm_year += real_year - 72; > #endif > > - if (century) > + if (century > 20) > time->tm_year += (century - 19) * 100; > > /* > -- > EW
Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > Does this mean that it is set to an invalid value and that in is not > getting updated properly in mc146818_set_time? It seems to be set/updated without trouble while the machine is on. It's only on a cold boot (from poweroff or hibernate) that the value is invalid. Patrick may be able to fill you in on more details.
On 06/01/2019 08:21:03+0000, Eric Wong wrote: > Older versions of Libreboot and Coreboot had an invalid value > (`3' in my case) in the century byte affecting the GM45 in > the Thinkpad X200. Not everybody's updated their firmwares, > and Linux <= 4.2 was able to read the RTC without problems, > so workaround this by ignoring invalid values. > > Fixes: 3c217e51d8a272b9 ("rtc: cmos: century support") > > Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> > Cc: Alessandro Zummo <a.zummo@towertech.it> > Cc: Sylvain Chouleur <sylvain.chouleur@intel.com> > Cc: Patrick McDermott <patrick.mcdermott@libiquity.com> > Cc: linux-rtc@vger.kernel.org > Signed-off-by: Eric Wong <e@80x24.org> > --- > drivers/rtc/rtc-mc146818-lib.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > Applied, thanks.
diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index 2f1772a358ca..18a6f15e313d 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -82,7 +82,7 @@ unsigned int mc146818_get_time(struct rtc_time *time) time->tm_year += real_year - 72; #endif - if (century) + if (century > 20) time->tm_year += (century - 19) * 100; /*
Older versions of Libreboot and Coreboot had an invalid value (`3' in my case) in the century byte affecting the GM45 in the Thinkpad X200. Not everybody's updated their firmwares, and Linux <= 4.2 was able to read the RTC without problems, so workaround this by ignoring invalid values. Fixes: 3c217e51d8a272b9 ("rtc: cmos: century support") Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Sylvain Chouleur <sylvain.chouleur@intel.com> Cc: Patrick McDermott <patrick.mcdermott@libiquity.com> Cc: linux-rtc@vger.kernel.org Signed-off-by: Eric Wong <e@80x24.org> --- drivers/rtc/rtc-mc146818-lib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)