Re: [1/3] drm/xe: Toggle the D3Cold enable flag at runtime resume

[Matthew Auld <matthew.auld@intel.com>]

On 16/10/2026 19:35, Belgaumkar, Vinay wrote:
> 
> On 10/16/2026 11:23 AM, Poosa, Karthik wrote:
>>
>> On 15-10-2026 22:24, Vinay Belgaumkar wrote:
>>> We enable this flag during runtime suspend,
>> i think there should be Fixes tag for this.
>>
>> Fixes: f026520367be ("drm/xe: Only set PCI d3cold_allowed when we are 
>> really allowing.")
> ok.
>>
>>> need to set it back to
>>> false early during resume to prevent any race with pci driver.
>> What is race that seen without this ?
> 
> While D0 is being programmed in xe_pci_runtime_resume(), pci driver's 
> internal auto suspend timer could expire and, since this d3cold flag is 
> still true, pci driver could try to put vsp into D3. This is probably 

I think needs more info here? We are in the RPM resume callback at this 
stage (RESUMING), so surely we are holding the required usage_count refs 
etc here, so how can it enter D3 here?


> why we toggle this flag as the very first thing in the S3 resume 
> function xe_pci_resume().
> 
> Thanks,
> 
> Vinay.
> 
>>>
>>> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
>>> ---
>>>   drivers/gpu/drm/xe/xe_pci.c | 3 +++
>>>   1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
>>> index 57c6f778ca24..2269e51868c1 100644
>>> --- a/drivers/gpu/drm/xe/xe_pci.c
>>> +++ b/drivers/gpu/drm/xe/xe_pci.c
>>> @@ -1450,6 +1450,9 @@ static int xe_pci_runtime_resume(struct device 
>>> *dev)
>>>       struct xe_device *xe = pdev_to_xe_device(pdev);
>>>       int err;
>>>   +    if (xe->d3cold.allowed)
>>> +        d3cold_toggle(pdev, D3COLD_DISABLE);
>>> +
>>>       err = pci_set_power_state(pdev, PCI_D0);
>>>       if (err)
>>>           return err;