linux-kernel - [PATCH] platform/x86: ISST: Allow reading core-power state on HWP disabled systems

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Date: Wed, 28 Feb 2024 16:26:59 -0800
From: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To: hdegoede@...hat.com,
	markgross@...nel.org,
	ilpo.jarvinen@...ux.intel.com,
	andriy.shevchenko@...ux.intel.com
Cc: platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: [PATCH] platform/x86: ISST: Allow reading core-power state on HWP disabled systems

When HWP (Hardware P-states) is disabled, dynamic SST features are
disabled. But user should still be able to read the current core-power
state, with legacy P-states. This will allow users to read current
configuration with static SST enabled from BIOS.

To address this, do not call disable_dynamic_sst_features() when the
request is for reading the state.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
---
 drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
index 2662fbbddf0c..1d918000d72b 100644
--- a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
+++ b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
@@ -462,10 +462,10 @@ static long isst_if_core_power_state(void __user *argp)
 	struct tpmi_per_power_domain_info *power_domain_info;
 	struct isst_core_power core_power;
 
-	if (disable_dynamic_sst_features())
+	if (copy_from_user(&core_power, argp, sizeof(core_power)))
 		return -EFAULT;
 
-	if (copy_from_user(&core_power, argp, sizeof(core_power)))
+	if (core_power.get_set && disable_dynamic_sst_features())
 		return -EFAULT;
 
 	power_domain_info = get_instance(core_power.socket_id, core_power.power_domain_id);
-- 
2.40.1