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

[Lazar, Lijo]

On 12/14/2023 10:15 PM, Mario Limonciello wrote:
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.


The fix needs to be in the return value of read_sensor() to return EBUSY 
or similar. That will also help other APIs calling read_sensor().

Regards,
Lijo

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

Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
---
  drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c | 20 +++++++++++---------
  1 file changed, 11 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 e1a5ee911dbb..5473fda5c6aa 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
@@ -1163,21 +1163,23 @@ 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);
+               if (!r && hotspot_tmp &&
+                   (hotspot_tmp / 1000 < range->software_shutdown_temp))
+                       return;
+               dev_warn(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");