Re: [PATCH v1 5/9] drm/amd/pm: use pm_runtime_get_if_active for debugfs getters

[Pierre-Eric Pelloux-Prayer]

Le 25/09/2024 à 15:35, Lazar, Lijo a écrit :


On 9/25/2024 1:24 PM, Pierre-Eric Pelloux-Prayer wrote:
Don't wake up the GPU for reading pm values. Instead, take a runtime
powermanagement ref when trying to read it iff the GPU is already
awake.

This avoids spurious wake ups (eg: from applets).

We use pm_runtime_get_if_in_active(ign_usage_count=true) because we care
about "is the GPU awake?" not about "is the GPU awake and something else
prevents suspend?".

Tested-by: Mario Limonciello <mario.limoncie...@amd.com>
Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-pra...@amd.com>
---
  drivers/gpu/drm/amd/pm/amdgpu_pm.c | 138 ++++++++++++++---------------
  1 file changed, 69 insertions(+), 69 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c 
b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
index c8f34b1a4d8e..f1f339b75380 100644
--- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
@@ -145,9 +145,9 @@ static ssize_t amdgpu_get_power_dpm_state(struct device 
*dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;

Not all our devices support runtime PM.

As per the API documentation -

"-EINVAL is returned if runtime PM is disabled for the
device, in which case also the usage_count will remain unmodified."

This doc is about "dev->power.disable_depth > 0", not about runtime PM being disabled (like you 
would get by using pm_runtime_forbid).

When runtime PM is disabled, usage_count is always >= 1 and the status is RPM_ACTIVE so 
pm_runtime_get_if_active will succeed.

I tested on 2 dGPUs without runtime PM, and both seemed to work fine.

Pierre-Eric


If that's true, this won't be working on devices without runtime PM support.

Thanks,
Lijo
  
  	amdgpu_dpm_get_current_power_state(adev, &pm);
  
@@ -268,9 +268,9 @@ static ssize_t amdgpu_get_power_dpm_force_performance_level(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	level = amdgpu_dpm_get_performance_level(adev);
  
@@ -364,9 +364,9 @@ static ssize_t amdgpu_get_pp_num_states(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	if (amdgpu_dpm_get_pp_num_states(adev, &data))
                memset(&data, 0, sizeof(data));
@@ -399,9 +399,9 @@ static ssize_t amdgpu_get_pp_cur_state(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	amdgpu_dpm_get_current_power_state(adev, &pm);
  
@@ -526,9 +526,9 @@ static ssize_t amdgpu_get_pp_table(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	size = amdgpu_dpm_get_pp_table(adev, &table);
  
@@ -840,9 +840,9 @@ static ssize_t amdgpu_get_pp_od_clk_voltage(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	for (clk_index = 0 ; clk_index < 6 ; clk_index++) {
                ret = amdgpu_dpm_emit_clock_levels(adev, od_clocks[clk_index], buf, 
&size);
@@ -930,9 +930,9 @@ static ssize_t amdgpu_get_pp_features(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	size = amdgpu_dpm_get_ppfeature_status(adev, buf);
        if (size <= 0)
@@ -996,9 +996,9 @@ static ssize_t amdgpu_get_pp_dpm_clock(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	ret = amdgpu_dpm_emit_clock_levels(adev, type, buf, &size);
        if (ret == -ENOENT)
@@ -1245,9 +1245,9 @@ static ssize_t amdgpu_get_pp_sclk_od(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	value = amdgpu_dpm_get_sclk_od(adev);
  
@@ -1302,9 +1302,9 @@ static ssize_t amdgpu_get_pp_mclk_od(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	value = amdgpu_dpm_get_mclk_od(adev);
  
@@ -1379,9 +1379,9 @@ static ssize_t amdgpu_get_pp_power_profile_mode(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	size = amdgpu_dpm_get_power_profile_mode(adev, buf);
        if (size <= 0)
@@ -1467,9 +1467,9 @@ static int amdgpu_hwmon_get_sensor_generic(struct 
amdgpu_device *adev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	r = pm_runtime_resume_and_get(adev->dev);
-       if (r < 0)
-               return r;
+       r = pm_runtime_get_if_active(adev->dev, true);
+       if (r <= 0)
+               return r ?: -EPERM;
  
  	/* get the sensor value */
        r = amdgpu_dpm_read_sensor(adev, sensor, query, &size);
@@ -1583,9 +1583,9 @@ static ssize_t amdgpu_get_pcie_bw(struct device *dev,
        if (!adev->asic_funcs->get_pcie_usage)
                return -ENODATA;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	amdgpu_asic_get_pcie_usage(adev, &count0, &count1);
  
@@ -1711,9 +1711,9 @@ static ssize_t amdgpu_get_apu_thermal_cap(struct device *dev,
        struct drm_device *ddev = dev_get_drvdata(dev);
        struct amdgpu_device *adev = drm_to_adev(ddev);
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	ret = amdgpu_dpm_get_apu_thermal_limit(adev, &limit);
        if (!ret)
@@ -1787,9 +1787,9 @@ static ssize_t amdgpu_get_pm_metrics(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	size = amdgpu_dpm_get_pm_metrics(adev, buf, PAGE_SIZE);
  
@@ -1825,9 +1825,9 @@ static ssize_t amdgpu_get_gpu_metrics(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(ddev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(ddev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	size = amdgpu_dpm_get_gpu_metrics(adev, &gpu_metrics);
        if (size <= 0)
@@ -2700,9 +2700,9 @@ static ssize_t amdgpu_hwmon_get_pwm1_enable(struct device 
*dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(adev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(adev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	ret = amdgpu_dpm_get_fan_control_mode(adev, &pwm_mode);
  
@@ -2828,9 +2828,9 @@ static ssize_t amdgpu_hwmon_get_pwm1(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	err = pm_runtime_resume_and_get(adev->dev);
-       if (err < 0)
-               return err;
+       err = pm_runtime_get_if_active(adev->dev, true);
+       if (err <= 0)
+               return err ?: -EPERM;
  
  	err = amdgpu_dpm_get_fan_speed_pwm(adev, &speed);
  
@@ -2855,9 +2855,9 @@ static ssize_t amdgpu_hwmon_get_fan1_input(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	err = pm_runtime_resume_and_get(adev->dev);
-       if (err < 0)
-               return err;
+       err = pm_runtime_get_if_active(adev->dev, true);
+       if (err <= 0)
+               return err ?: -EPERM;
  
  	err = amdgpu_dpm_get_fan_speed_rpm(adev, &speed);
  
@@ -2916,9 +2916,9 @@ static ssize_t amdgpu_hwmon_get_fan1_target(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	err = pm_runtime_resume_and_get(adev->dev);
-       if (err < 0)
-               return err;
+       err = pm_runtime_get_if_active(adev->dev, true);
+       if (err <= 0)
+               return err ?: -EPERM;
  
  	err = amdgpu_dpm_get_fan_speed_rpm(adev, &rpm);
  
@@ -2986,9 +2986,9 @@ static ssize_t amdgpu_hwmon_get_fan1_enable(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(adev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(adev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	ret = amdgpu_dpm_get_fan_control_mode(adev, &pwm_mode);
  
@@ -3152,9 +3152,9 @@ static ssize_t amdgpu_hwmon_show_power_cap_generic(struct device *dev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	r = pm_runtime_resume_and_get(adev->dev);
-       if (r < 0)
-               return r;
+       r = pm_runtime_get_if_active(adev->dev, true);
+       if (r <= 0)
+               return r ?: -EPERM;
  
  	r = amdgpu_dpm_get_power_limit(adev, &limit,
                                      pp_limit_level, power_type);
@@ -3685,9 +3685,9 @@ static int amdgpu_retrieve_od_settings(struct 
amdgpu_device *adev,
        if (adev->in_suspend && !adev->in_runpm)
                return -EPERM;
  
-	ret = pm_runtime_resume_and_get(adev->dev);
-       if (ret < 0)
-               return ret;
+       ret = pm_runtime_get_if_active(adev->dev, true);
+       if (ret <= 0)
+               return ret ?: -EPERM;
  
  	size = amdgpu_dpm_print_clock_levels(adev, od_type, buf);
        if (size == 0)