[PATCH V4 17/17] drm/amd/pm: unified lock protections in amdgpu_dpm.c

[Arthur Marsh <arthur.marsh@xxxxxxxxxxxxxxxx>]

Hi, short answer is that with both patches applied, I am successfully running
the amdgpu kernel module on radeonsi (plasma desktop on X.org).

I confirmed that CONFIG_LOCKDEP_SUPPORT=y is enabled in the kernel.

With the first patch applied and remotely connecting to the machine and
loading amdgpu via:

modprobe amdgpu si_support=1 gpu_recovery=1

the last lines of dmesg were:

[  264.095969] [drm] Found UVD firmware Version: 64.0 Family ID: 13
[  264.097779] [drm] PCIE gen 2 link speeds already enabled
[  264.648137] [drm] UVD initialized successfully.
[  264.648696] amdgpu 0000:01:00.0: amdgpu: SE 1, SH per SE 2, CU per SH 5, active_cu_number 8
[  264.984814] [drm] Initialized amdgpu 3.46.0 20150101 for 0000:01:00.0 on minor 0
[  265.040280] fbcon: amdgpudrmfb (fb0) is primary device

After applying the second patch and building and restarting with the new
kernel, I could load amdgpu successfuly and start
the plasma desktop under X.org, with the last amdgpu load lines being:

[  227.736281] fbcon: amdgpudrmfb (fb0) is primary device
[  227.760719] Console: switching to colour frame buffer device 240x67
[  227.765024] amdgpu 0000:01:00.0: [drm] fb0: amdgpudrmfb frame buffer device

I tried building a kernel with just the second patch and that experienced
a lockup after apparently loading amdgpu alright.

First and second patches combined:

diff --git a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
index 89fbee568be4..e9ebbc9f4cd2 100644
--- a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
+++ b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
@@ -80,8 +80,6 @@ int amdgpu_dpm_set_powergating_by_smu(struct amdgpu_device *adev, uint32_t block
 		return 0;
 	}
 
-	mutex_lock(&adev->pm.mutex);
-
 	switch (block_type) {
 	case AMD_IP_BLOCK_TYPE_UVD:
 	case AMD_IP_BLOCK_TYPE_VCE:
@@ -102,8 +100,6 @@ int amdgpu_dpm_set_powergating_by_smu(struct amdgpu_device *adev, uint32_t block
 	if (!ret)
 		atomic_set(&adev->pm.pwr_state[block_type], pwr_state);
 
-	mutex_unlock(&adev->pm.mutex);
-
 	return ret;
 }
 
@@ -423,9 +419,7 @@ void amdgpu_dpm_compute_clocks(struct amdgpu_device *adev)
 	if (!pp_funcs->pm_compute_clocks)
 		return;
 
-	mutex_lock(&adev->pm.mutex);
 	pp_funcs->pm_compute_clocks(adev->powerplay.pp_handle);
-	mutex_unlock(&adev->pm.mutex);
 }
 
 void amdgpu_dpm_enable_uvd(struct amdgpu_device *adev, bool enable)

Thanks for the assistance!

Arthur.