This is a note to let you know that I've just added the patch titled rtc: opal: Handle disabled TPO in opal_get_tpo_time() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rtc-opal-handle-disabled-tpo-in-opal_get_tpo_time.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Tue Apr 10 10:31:53 CEST 2018 From: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx> Date: Fri, 19 May 2017 15:35:09 +0530 Subject: rtc: opal: Handle disabled TPO in opal_get_tpo_time() From: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx> [ Upstream commit 6dc1cf6f932bb0ea4d8f5e913a0a401ecacd2f03 ] On PowerNV platform when Timed-Power-On(TPO) is disabled, read of stored TPO yields value with all date components set to '0' inside opal_get_tpo_time(). The function opal_to_tm() then converts it to an offset from year 1900 yielding alarm-time == "1900-00-01 00:00:00". This causes problems with __rtc_read_alarm() that expecting an offset from "1970-00-01 00:00:00" and returned alarm-time results in a -ve value for time64_t. Which ultimately results in this error reported in kernel logs with a seemingly garbage value: "rtc rtc0: invalid alarm value: -2-1--1041528741 2005511117:71582844:32" We fix this by explicitly handling the case of all alarm date-time components being '0' inside opal_get_tpo_time() and returning -ENOENT in such a case. This signals generic rtc that no alarm is set and it bails out from the alarm initialization flow without reporting the above error. Signed-off-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx> Reported-by: Steve Best <sbest@xxxxxxxxxx> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/rtc/rtc-opal.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/drivers/rtc/rtc-opal.c +++ b/drivers/rtc/rtc-opal.c @@ -150,6 +150,16 @@ static int opal_get_tpo_time(struct devi y_m_d = be32_to_cpu(__y_m_d); h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32); + + /* check if no alarm is set */ + if (y_m_d == 0 && h_m_s_ms == 0) { + pr_debug("No alarm is set\n"); + rc = -ENOENT; + goto exit; + } else { + pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms); + } + opal_to_tm(y_m_d, h_m_s_ms, &alarm->time); exit: Patches currently in stable-queue which might be from vaibhav@xxxxxxxxxxxxxxxxxx are queue-4.4/rtc-interface-validate-alarm-time-before-handling-rollover.patch queue-4.4/rtc-opal-handle-disabled-tpo-in-opal_get_tpo_time.patch