Re: [PATCH] drm/amd: Require CONFIG_HOTPLUG_PCI_PCIE for BOCO

[Mario Limonciello <superm1@kernel.org>]

On 12/11/2024 14:08, Alex Deucher wrote:
> On Wed, Dec 11, 2024 at 10:56 AM Mario Limonciello <superm1@kernel.org> wrote:
>>
>> From: Mario Limonciello <mario.limonciello@amd.com>
>>
>> If the kernel hasn't been compiled with PCIe hotplug support this
>> can lead to problems with dGPUs that use BOCO because they effectively
>> drop off the bus.
>>
>> To prevent issues, disable BOCO support when compiled without PCIe hotplug.
>>
>> Reported-by: Gabriel Marcano <gabemarcano@yahoo.com>
>> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/1707#note_2696862
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> 
> Acked-by: Alex Deucher <alexander.deucher@amd.com>

Thx.

> 
> Seems like this should affect any device which supports d3cold.  Maybe
> we want something more general as well?

Any specific ideas?  One of these two hunks I think make sense, leaning 
upon the second one more strongly.
  
  
  
                                   diff --git a/drivers/pci/pci.c 
b/drivers/pci/pci.c
index 0b29ec6e8e5e2..01691f1d26fbe 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2751,6 +2751,10 @@ int pci_prepare_to_sleep(struct pci_dev *dev)
         if (target_state == PCI_POWER_ERROR)
                 return -EIO;

+       if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE) &&
+           target_state == PCI_D3cold)
+               return -EBUSY;
+
         pci_enable_wake(dev, target_state, wakeup);

         error = pci_set_power_state(dev, target_state);
@@ -2797,6 +2801,10 @@ int pci_finish_runtime_suspend(struct pci_dev *dev)
         if (target_state == PCI_POWER_ERROR)
                 return -EIO;

+       if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE) &&
+            target_state == PCI_D3cold)
+               return -EBUSY;
+
         __pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));

         error = pci_set_power_state(dev, target_state);
> 
> Alex
> 
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index 764d41434a82f..7db796ebb967e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -419,6 +419,9 @@ bool amdgpu_device_supports_boco(struct drm_device *dev)
>>   {
>>          struct amdgpu_device *adev = drm_to_adev(dev);
>>
>> +       if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE))
>> +               return false;
>> +
>>          if (adev->has_pr3 ||
>>              ((adev->flags & AMD_IS_PX) && amdgpu_is_atpx_hybrid()))
>>                  return true;
>> --
>> 2.43.0
>>