[PATCH v1] cpufreq: intel_pstate: Skip HWP_CAP reads in Broadwell mode

["Rafael J. Wysocki" <rafael@kernel.org>]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

When running in the Broadwell HWP mode, the turbo, max and min
P-state values are retrieved from MSR_PLATFORM_INFO, so reading
MSR_HWP_CAPABILITIES in that mode in order to update those values
is pointless.  Moreover, using the MSR_HWP_CAPABILITIES value for
updating them in the Broadwell mode may be harmful, so avoid doing
that altogether.

Fixes: de5bcf404ace ("cpufreq: intel_pstate: Clean up frequency computations")
Link: https://sashiko.dev/#/patchset/6005456.DvuYhMxLoT%40rafael.j.wysocki
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: All applicable <stable@vger.kernel.org>
---
 drivers/cpufreq/intel_pstate.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -1197,6 +1197,9 @@ static void intel_pstate_get_hwp_cap(str
 {
 	int scaling = cpu->pstate.scaling;
 
+	if (hwp_mode_bdw)
+		return;
+
 	__intel_pstate_get_hwp_cap(cpu);
 
 	cpu->pstate.max_freq = cpu->pstate.max_pstate * scaling;