1. 16 Jun, 2011 2 commits
    • Konrad Rzeszutek Wilk's avatar
      [CPUFREQ] powernow-k8: Don't notify of successful transition if we failed (vid case). · a9d3d206
      Konrad Rzeszutek Wilk authored
      Before this patch if we failed the vid transition would still try to
      submit the "new" frequencies to cpufreq.
      That is incorrect - also we could submit a non-existing frequency value
      which would cause cpufreq to crash. The ultimate fix is in cpufreq
      to deal with incorrect values, but this patch improves the error
      recovery in the AMD powernowk8 driver.
      
      The failure that was reported was as follows:
      
      powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3700+ (1 cpu cores) (version 2.20.00)
      powernow-k8: fid 0x2 (1000 MHz), vid 0x12
      powernow-k8: fid 0xa (1800 MHz), vid 0xa
      powernow-k8: fid 0xc (2000 MHz), vid 0x8
      powernow-k8: fid 0xe (2200 MHz), vid 0x8
      Marking TSC unstable due to cpufreq changes
      powernow-k8: fid trans failed, fid 0x2, curr 0x0
      BUG: unable to handle kernel paging request at ffff880807e07b78
      IP: [<ffffffff81479163>] cpufreq_stats_update+0x46/0x5b
      ...
      
      And transition fails and data->currfid ends up with 0. Since
      the machine does not support 800Mhz value when the calculation is
      done ('find_khz_freq_from_fid(data->currfid);') it reports the
      new frequency as 800000 which is bogus. This patch fixes
      the issue during target setting.
      
      The patch however does not fix the issue in 'powernowk8_cpu_init'
      where the pol->cur can also be set with the 800000 value:
      
                pol->cur = find_khz_freq_from_fid(data->currfid);
        dprintk("policy current frequency %d kHz\n", pol->cur);
      
        /* min/max the cpu is capable of */
        if (cpufreq_frequency_table_cpuinfo(pol, data->powernow_table)) {
      
      The fix for that looks to update cpufreq_frequency_table_cpuinfo to
      check pol->cur.... but that would cause an regression in how the
      acpi-cpufreq driver works (it sets cpu->cur after calling
      cpufreq_frequency_table_cpuinfo). Instead the fix will be to let
      cpufreq gracefully handle bogus data (another patch).
      Acked-by: default avatarBorislav Petkov <bp@alien8.de>
      CC: andre.przywara@amd.com
      CC: Mark.Langsdorf@amd.com
      Reported-by: default avatarTobias Diedrich <ranma+xen@tdiedrich.de>
      Tested-by: default avatarTobias Diedrich <ranma+xen@tdiedrich.de>
      [v1: Rebased on v3.0-rc2, reduced patch to deal with vid case]
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Signed-off-by: default avatarDave Jones <davej@redhat.com>
      a9d3d206
    • Konrad Rzeszutek Wilk's avatar
      [CPUFREQ] Don't set stat->last_index to -1 if the pol->cur has incorrect value. · 46a310b8
      Konrad Rzeszutek Wilk authored
      If the driver submitted an non-existing pol>cur value (say it
      used the default initialized value of zero), when the cpufreq
      stats tries to setup its initial values it incorrectly sets
      stat->last_index to -1 (or 0xfffff...). And cpufreq_stats_update
      tries to update at that index location and fails.
      
      This can be caused by:
      
      stat->last_index = freq_table_get_index(stat, policy->cur);
      
      not finding the appropiate frequency in the table (b/c the policy->cur
      is wrong) and we end up crashing. The fix however is
      concentrated in the 'cpufreq_stats_update' as the last_index
      (and old_index) are updated there. Which means it can reset
      the last_index to -1 again and on the next iteration cause a crash.
      
      Without this patch, the following crash is observed:
      
      powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3700+ (1 cpu cores) (version 2.20.00)
      powernow-k8: fid 0x2 (1000 MHz), vid 0x12
      powernow-k8: fid 0xa (1800 MHz), vid 0xa
      powernow-k8: fid 0xc (2000 MHz), vid 0x8
      powernow-k8: fid 0xe (2200 MHz), vid 0x8
      Marking TSC unstable due to cpufreq changes
      powernow-k8: fid trans failed, fid 0x2, curr 0x0
      BUG: unable to handle kernel paging request at ffff880807e07b78
      IP: [<ffffffff81479163>] cpufreq_stats_update+0x46/0x5b
      .. snip..
      Pid: 1, comm: swapper Not tainted 3.0.0-rc2 #45 MICRO-STAR INTERNATIONAL CO., LTD MS-7094/MS-7094
      ..snip..
      Call Trace:
       [<ffffffff81479248>] cpufreq_stat_notifier_trans+0x48/0x7c
       [<ffffffff81095d68>] notifier_call_chain+0x32/0x5e
       [<ffffffff81095e6b>] __srcu_notifier_call_chain+0x47/0x63
       [<ffffffff81095e96>] srcu_notifier_call_chain+0xf/0x11
       [<ffffffff81477e7a>] cpufreq_notify_transition+0x111/0x134
       [<ffffffff8147b0d4>] powernowk8_target+0x53b/0x617
       [<ffffffff8147723a>] __cpufreq_driver_target+0x2e/0x30
       [<ffffffff8147a127>] cpufreq_governor_dbs+0x339/0x356
       [<ffffffff81477394>] __cpufreq_governor+0xa8/0xe9
       [<ffffffff81477525>] __cpufreq_set_policy+0x132/0x13e
       [<ffffffff8147848d>] cpufreq_add_dev_interface+0x272/0x28c
      Reported-by: default avatarTobias Diedrich <ranma+xen@tdiedrich.de>
      Tested-by: default avatarTobias Diedrich <ranma+xen@tdiedrich.de>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Signed-off-by: default avatarDave Jones <davej@redhat.com>
      46a310b8
  2. 15 Jun, 2011 1 commit
  3. 14 Jun, 2011 27 commits
  4. 13 Jun, 2011 10 commits