touch-packages team mailing list archive

[Doug Smythies <1493156@xxxxxxxxxxxxxxxxxx>]

As of kernel 4.4-rc1 this bug becomes invalid, as the kernel was patched such that this issue no longer occurs.
I'll wait until kernel 4.4 is finished, check again, then set the status of this bug report to invalid.

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https://bugs.launchpad.net/bugs/1493156

Title:
  pm-suspend aborts if highest numbered CPU offline, as of kernel 4.2

Status in pm-utils package in Ubuntu:
  New

Bug description:
  Kernel 4.2 includes a significant commit
  (87549141d516aee71d511138e27117c41e8aef68), after the patch the files
  and directory are present even if the CPU is offline. If the CPU is
  offline, writing to those files isn't allowed and so the echo in
  94cpufreq fails.

  If the failed echo is not the last pass through the loop, then
  the bad exit code gets overwritten with a good one before
  the loop exits. If the failed echo is the last pass through the loop, due to the highest numbered CPU being offline, then then 94cpufreq returns an error code and pm-suspend aborts.

  So what is needed is something like (and this doesn't actually work
  yet):

  hibernate_cpufreq()
  {
          ( cd /sys/devices/system/cpu/
          for x in cpu[0-9]*; do
                  # if cpufreq is a symlink, it is handled by another cpu. Skip.
                  [ -L "$x/cpufreq" ] && continue
                  gov="$x/cpufreq/scaling_governor"
                  # if we do not have a scaling_governor file, skip.
                  [ -f "$gov" ] || continue

  +               # if the CPU is offline, skip, unless no file, i.e. CPU0.
  +               [ $(cat "$x/online") = "1" -o ! -f "$x/online" ] || continue
  Or
  +               if [ $(cat "$x/online") = "1" ] || [ ! -f "$x/online" ]; then
  +                       continue;
  +                fi
  Or something similar that actually works.

                  # if our temporary governor is not available, skip.
                  grep -q "$TEMPORARY_CPUFREQ_GOVERNOR" \
                          "$x/cpufreq/scaling_available_governors" || continue
                  savestate "${x}_governor" < "$gov"
                  echo "$TEMPORARY_CPUFREQ_GOVERNOR" > "$gov"
          done )
  }

  Or just force a good return code at the end (which is what I'm doing
  now, so that I can move on).

  Note: I also filed this same bug report upstream.
  https://bugs.freedesktop.org/show_bug.cgi?id=91914

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