[PATCH AUTOSEL 4.19 20/26] cpufreq: intel_pstate: Refuse to turn off with HWP enabled

[PATCH AUTOSEL 4.19 20/26] cpufreq: intel_pstate: Refuse to turn off with HWP enabled

[Sasha Levin]

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

[ Upstream commit 43298db3009f06fe5c69e1ca8b6cfc2565772fa1 ]

After commit f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive
mode with HWP enabled") it is possible to change the driver status
to "off" via sysfs with HWP enabled, which effectively causes the
driver to unregister itself, but HWP remains active and it forces the
minimum performance, so even if another cpufreq driver is loaded,
it will not be able to control the CPU frequency.

For this reason, make the driver refuse to change the status to
"off" with HWP enabled.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cpufreq/intel_pstate.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 99166000ffb77..8fa22aa2ac65b 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -2325,9 +2325,15 @@ static int intel_pstate_update_status(const char *buf, size_t size)
 {
 	int ret;
 
-	if (size == 3 && !strncmp(buf, "off", size))
-		return intel_pstate_driver ?
-			intel_pstate_unregister_driver() : -EINVAL;
+	if (size == 3 && !strncmp(buf, "off", size)) {
+		if (!intel_pstate_driver)
+			return -EINVAL;
+
+		if (hwp_active)
+			return -EBUSY;
+
+		return intel_pstate_unregister_driver();
+	}
 
 	if (size == 6 && !strncmp(buf, "active", size)) {
 		if (intel_pstate_driver) {
-- 
2.25.1

[PATCH AUTOSEL 4.19 21/26] cpufreq: intel_pstate: Fix intel_pstate_get_hwp_max() for turbo disabled

[Sasha Levin]

From: Francisco Jerez <currojerez@riseup.net>

[ Upstream commit eacc9c5a927e474c173a5d53dd7fb8e306511768 ]

This fixes the behavior of the scaling_max_freq and scaling_min_freq
sysfs files in systems which had turbo disabled by the BIOS.

Caleb noticed that the HWP is programmed to operate in the wrong
P-state range on his system when the CPUFREQ policy min/max frequency
is set via sysfs.  This seems to be because in his system
intel_pstate_get_hwp_max() is returning the maximum turbo P-state even
though turbo was disabled by the BIOS, which causes intel_pstate to
scale kHz frequencies incorrectly e.g. setting the maximum turbo
frequency whenever the maximum guaranteed frequency is requested via
sysfs.

Tested-by: Caleb Callaway <caleb.callaway@intel.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Minor subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cpufreq/intel_pstate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 8fa22aa2ac65b..864a7e8ebdfc3 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -712,7 +712,7 @@ static void intel_pstate_get_hwp_max(unsigned int cpu, int *phy_max,
 
 	rdmsrl_on_cpu(cpu, MSR_HWP_CAPABILITIES, &cap);
 	WRITE_ONCE(all_cpu_data[cpu]->hwp_cap_cached, cap);
-	if (global.no_turbo)
+	if (global.no_turbo || global.turbo_disabled)
 		*current_max = HWP_GUARANTEED_PERF(cap);
 	else
 		*current_max = HWP_HIGHEST_PERF(cap);
-- 
2.25.1