pcc-cpufreq: don't load driver if get_freq fails during init.

commit 1f858ef2fbabdc5e645644010a31a40c32e397c9 upstream.

Return 0 on failure. This will cause the initialization of the driver
to fail and prevent the driver from loading if the BIOS cannot handle
the PCC interface command to "get frequency". Otherwise, the driver
will load and display a very high value like "4294967274" (which is
actually -EINVAL) for frequency:

# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
4294967274

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
index 4f6f679f27990198640f9a1e139ea3a838b05eb8..4a5a42b842adfcc457f77745584eaca3c7882bdd 100644 (file)
--- a/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
@@ -195,7 +195,7 @@ static unsigned int pcc_get_freq(unsigned int cpu)
 cmd_incomplete:
        iowrite16(0, &pcch_hdr->status);
        spin_unlock(&pcc_lock);
-       return -EINVAL;
+       return 0;
 }
 
 static int pcc_cpufreq_target(struct cpufreq_policy *policy,