Alexandre Belloni alexandre.belloni@bootlin.com writes:
On 02/08/2016 at 11:50:16 +1000, Stewart Smith wrote:
According to the OPAL docs: https://github.com/open-power/skiboot/blob/skiboot-5.2.5/doc/opal-api/opal-r... https://github.com/open-power/skiboot/blob/skiboot-5.2.5/doc/opal-api/opal-r... OPAL_HARDWARE may be returned from OPAL_RTC_READ or OPAL_RTC_WRITE and this indicates either a transient or permanent error.
Prior to this patch, Linux was not dealing with OPAL_HARDWARE being a permanent error particularly well, in that you could end up in a busy loop.
This was not too hard to trigger on an AMI BMC based OpenPOWER machine doing a continuous "ipmitool mc reset cold" to the BMC, the result of that being that we'd get stuck in an infinite loop in opal_get_rtc_time.
We now retry a few times before returning the error higher up the stack.
Cc: stable@vger.kernel.org Signed-off-by: Stewart Smith stewart@linux.vnet.ibm.com
drivers/rtc/rtc-opal.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
Just a note to let you know that this patch should have gone through my tree but it was not sent to linux-rtc or me.
I guess what happened is that Michael cleaned up the Linux PPC patchwork queue.
Apologies for not sending there. My (18 month ago self) bad.