path: root/drivers/cpufreq/powernow-k8.c
diff options
authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-06-16 15:36:39 -0400
committerDave Jones <davej@redhat.com>2011-06-16 16:31:13 -0400
commita9d3d2068064b7a6395871a49616d3784f802d50 (patch)
treead523f8e5c941cc41819fb4fd8f8746fb1fe8499 /drivers/cpufreq/powernow-k8.c
parent46a310b80bc2c9ccc019649c9da91194cbc10944 (diff)
[CPUFREQ] powernow-k8: Don't notify of successful transition if we failed (vid case).
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: Borislav Petkov <bp@alien8.de> CC: andre.przywara@amd.com CC: Mark.Langsdorf@amd.com Reported-by: Tobias Diedrich <ranma+xen@tdiedrich.de> Tested-by: Tobias Diedrich <ranma+xen@tdiedrich.de> [v1: Rebased on v3.0-rc2, reduced patch to deal with vid case] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'drivers/cpufreq/powernow-k8.c')
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 83479b6fb9a1..287c56f6749a 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1079,6 +1079,9 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
res = transition_fid_vid(data, fid, vid);
+ if (res)
+ return res;
freqs.new = find_khz_freq_from_fid(data->currfid);
for_each_cpu(i, data->available_cores) {