[SRU][Bionic][PATCH 0/2] Fixes for LP:1773964

Joseph Salisbury joseph.salisbury at canonical.com
Wed Jun 13 15:10:06 UTC 2018

BugLink: http://bugs.launchpad.net/bugs/1773964

== SRU Justification ==
IBM is requesting these two commits in powerpc to fix an error they are
IPL: ppc64_cpu --frequency hang with INFO: rcu_sched detected stalls on 
CPUs/tasks on w34 and wsbmc016 with 920.1714.20170330n

The first commit reduces some existing high latency delays.  The second
commit fixes the fact that the OPAL RTC driver does not sleep in case it gets OPAL_BUSY or
OPAL_BUSY_EVENT from firmware.

== Fixes ==
34dd25de9fe3 ("powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops")
682e6b4da5cb ("rtc: opal: Fix OPAL RTC driver OPAL_BUSY loops")

== Regression Potential ==
Low.  The first commit is specific to powerpc.  The second commit is, commit 628daa8d5abf 
and it been cc'd to upstream stable to fix a regression, so it has had
additional upstream review.

== Test Case ==
A test kernel was built with these patches and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug. 

Nicholas Piggin (2):
  powerpc/powernv: define a standard delay for OPAL_BUSY type retry
  rtc: opal: Fix OPAL RTC driver OPAL_BUSY loops

 arch/powerpc/include/asm/opal.h           |  3 +++
 arch/powerpc/platforms/powernv/opal-rtc.c |  8 ++++---
 drivers/rtc/rtc-opal.c                    | 37 +++++++++++++++++++------------
 3 files changed, 31 insertions(+), 17 deletions(-)


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