[PATCH v3 2/3] drm/amd: Make SW CTF handler cope with different read_sensor() results

[Mario Limonciello]

The SW CTF handler assumes that the read_sensor() call always succeeds
and has updated `hotspot_tmp`, but this may not be guaranteed.

For example some of the read_sensor() callbacks will return 0 when a RAS
interrupt is triggered in which case `hotspot_tmp` won't be updated.

Adjust the logic to catch this circumstance and output a warning.

Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
---
v2->v3:
 * Correctly handle fallthrough case
v1->v2:
 * Only show `Failed to read hotspot temperature` when sensor read fails
---
 drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c | 24 ++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
index d24fccf28f6a..963cf6e76935 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
@@ -1165,21 +1165,27 @@ static void smu_swctf_delayed_work_handler(struct work_struct *work)
 	struct smu_temperature_range *range =
 				&smu->thermal_range;
 	struct amdgpu_device *adev = smu->adev;
-	uint32_t hotspot_tmp, size;
+	uint32_t hotspot_tmp = 0, size;
 
 	/*
 	 * If the hotspot temperature is confirmed as below SW CTF setting point
 	 * after the delay enforced, nothing will be done.
 	 * Otherwise, a graceful shutdown will be performed to prevent further damage.
 	 */
-	if (range->software_shutdown_temp &&
-	    smu->ppt_funcs->read_sensor &&
-	    !smu->ppt_funcs->read_sensor(smu,
-					 AMDGPU_PP_SENSOR_HOTSPOT_TEMP,
-					 &hotspot_tmp,
-					 &size) &&
-	    hotspot_tmp / 1000 < range->software_shutdown_temp)
-		return;
+	if (range->software_shutdown_temp && smu->ppt_funcs->read_sensor) {
+		int r = smu->ppt_funcs->read_sensor(smu,
+						    AMDGPU_PP_SENSOR_HOTSPOT_TEMP,
+						    &hotspot_tmp,
+						    &size);
+		switch (r) {
+		case 0:
+			if (hotspot_tmp / 1000 < range->software_shutdown_temp)
+				return;
+			break;
+		default:
+			dev_err(adev->dev, "Failed to read hotspot temperature: %d\n", r);
+		}
+	}
 
 	dev_emerg(adev->dev, "ERROR: GPU over temperature range(SW CTF) detected!\n");
 	dev_emerg(adev->dev, "ERROR: System is going to shutdown due to GPU SW CTF!\n");
-- 
2.34.1