Re: PCI device hot insert is not detected

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

On 12/12/2023 05:32, Ashutosh Sharma wrote:
>> This doesn't work, try "echo 1 | sudo tee power" instead.
> 
> This was not a permission issue, I already gave it read/write permission.
> 
> admin@node-4:/sys/bus/pci/slots/14$ sudo echo 1 > power
> -bash: power: Permission denied
> admin@node-4:/sys/bus/pci/slots/14$ sudo chmod 0666 power
> admin@node-4:/sys/bus/pci/slots/14$ sudo echo 1 > power
> echo: write error: Operation not permitted
> admin@node-4:/sys/bus/pci/slots/14$
> 
>> This is from a "Link up" situation (DLActive+), it would be more
>> interesting to get lspci output of the port in a "No link" situation.
> 
> Unfortunately, I did not collect that output before system reboot.
> 
> On Tue, 12 Dec 2023 at 16:29, Lukas Wunner <lukas@wunner.de> wrote:
>>
>> On Tue, Dec 12, 2023 at 04:04:41PM +0530, Ashutosh Sharma wrote:
>>> Removed one NVMe drive (pci address 0000:83:00.0), it got unbound
>>> successfully from "vfio-pci" driver but saw below error in the syslog.
>>>
>>> can't change power state from D0 to D3hot (config space inaccessible)
>>
>> This is normal, the drive's config space is inaccessible after removal.
>>

Was the removal a "surprise" removal?  Or you mean it was by using 
'remove' sysfs file?

IIRC surprise removal will need platform firmware support to handle it 
properly.

>>
>>> Then after 2:30 min approx, re-inserted the same drive to the same PCI
>>> slot. But the drive was not detected.
>>>
>>> Dec 11 23:54:39 node-4 kernel: [183672.630191] pcieport 0000:80:03.2:
>>> pciehp: Slot(14): Attention button pressed
>>> Dec 11 23:54:39 node-4 kernel: [183672.630195] pcieport 0000:80:03.2:
>>> pciehp: Slot(14) Powering on due to button press
>>> Dec 11 23:54:44 node-4 kernel: [183677.671931] pcieport 0000:80:03.2:
>>> pciehp: Slot(14): Card present
>>> Dec 11 23:54:46 node-4 kernel: [183679.783922] pcieport 0000:80:03.2:
>>> pciehp: Slot(14): No link
>>
>> The link doesn't come up, so the kernel gives up on the slot.
>>
>> I don't know what the reason is, could be a hardware issue or
>> protocol incompatibility.  This doesn't look like a kernel issue.
>>
>>
>>>   |           +-03.0  Advanced Micro Devices, Inc. [AMD]
>>> Starship/Matisse PCIe Dummy Host Bridge
>>>   |           +-03.1-[82]----00.0  Samsung Electronics Co Ltd NVMe SSD
>>> Controller PM9A1/PM9A3/980PRO
>>>   |           +-03.2-[83]--
>>
>> Adding Mario, Smita, Yazen from AMD to cc, maybe they have an idea
>> what the issue is or how to get diagnostics on this Epyc platform.
>>
>> Start of thread:
>> https://lore.kernel.org/linux-pci/CADOvten7jG7KjW6W1MRd7i8_E18L0xCCaCzmZOY_vvgJhdfOSw@mail.gmail.com/
>>
>>
>>> admin@node-4:/sys/bus/pci/slots/14$ sudo echo 1 > power
>>> echo: write error: Operation not permitted
>>
>> This doesn't work, try "echo 1 | sudo tee power" instead.
>>
>>
>>> lspci output of the pci port:
>>> 80:03.2 PCI bridge: Advanced Micro Devices, Inc. [AMD]
>>> Starship/Matisse GPP Bridge (prog-if 00 [Normal decode])
>> [...]
>>>                  LnkSta: Speed 16GT/s (ok), Width x4 (ok)
>>>                          TrErr- Train- SlotClk+ DLActive+ BWMgmt+ ABWMgmt-
>>
>> This is from a "Link up" situation (DLActive+), it would be more
>> interesting to get lspci output of the port in a "No link" situation.
>>
>> Thanks,
>>
>> Lukas