Re: PCI device hot insert is not detected

[Lukas Wunner <lukas@wunner.de>]

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.


> 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