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author | Stewart Smith <stewart@linux.vnet.ibm.com> | 2016-08-02 03:50:16 +0200 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-01-27 11:15:59 +0100 |
commit | 5b8b58063029f02da573120ef4dc9079822e3cda (patch) | |
tree | 1e253d31ee131d57812aa4c6df385b5248fea2ad /Documentation/filesystems/dax.txt | |
parent | powerpc/mpc52xx_gpt: make use of raw_spinlock variants (diff) | |
download | linux-5b8b58063029f02da573120ef4dc9079822e3cda.tar.xz linux-5b8b58063029f02da573120ef4dc9079822e3cda.zip |
rtc-opal: Fix handling of firmware error codes, prevent busy loops
According to the OPAL docs:
skiboot-5.2.5/doc/opal-api/opal-rtc-read-3.txt
skiboot-5.2.5/doc/opal-api/opal-rtc-write-4.txt
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.
Fixes: 16b1d26e77b1 ("rtc/tpo: Driver to support rtc and wakeup on PowerNV platform")
Cc: stable@vger.kernel.org # v3.19+
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'Documentation/filesystems/dax.txt')
0 files changed, 0 insertions, 0 deletions