Re: [PATCH v18 2/2] PCI: Add a quirk for AMD PCIe root ports w/ USB4 controllers

[Mario Limonciello <mario.limonciello@amd.com>]

On 9/13/2023 09:31, Lukas Wunner wrote:
> On Tue, Sep 12, 2023 at 11:43:53PM -0500, Mario Limonciello wrote:
>> On 9/12/2023 23:25, Lukas Wunner wrote:
>>> There's already PCI_DEV_FLAGS_NO_D3, would it be possible to just
>>> reuse that instead of adding another codepath for D3 quirks?
>>>
>>
>> The root port can handle D3 (including wakeup) at runtime fine.
>> Issue occurs only during s2idle w/ hardware sleep.
> 
> I see.
> 
> If this only affects system sleep, not runtime PM, what you can do is
> define a DECLARE_PCI_FIXUP_SUSPEND_LATE() which calls pci_d3cold_disable()
> and also define a DECLARE_PCI_FIXUP_CLASS_RESUME_EARLY() which calls
> pci_d3cold_enable().
> 
> And I think you can make those calls conditional on pm_suspend_no_platform()
> to constrain to s2idle.
> 
> User space should still be able to influence runtime PM via the
> d3cold_allowed flag (unless I'm missing something).
> 
> Thanks,
> 
> Lukas

The part you're missing is that D3hot is affected by this issue too, 
otherwise it would be a good proposal.