External PCIe device disconnected at driver load

Robotics & Edge Computing Jetson Systems Jetson Thor
1

I am connecting an external PCIe device on Jetson AGX Thor, but it is disconnected at driver load.

In the dmsg.txt I see the AER of the issue:

[ 15.280087] pcieport 0001:00:00.0: AER: Correctable error message received from 0001:00:00.0

[ 15.280104] pcieport 0001:00:00.0: DPC: containment event, status:0x3f01 source:0x0000

[ 15.280110] pcieport 0001:00:00.0: DPC: unmasked uncorrectable error detected

[ 15.280127] pcieport 0001:00:00.0: AER: found no error details for 0001:00:00.0

[ 15.280154] pcieport 0001:00:00.0: PCIe Bus Error: severity=Uncorrectable (Fatal), type=Transaction Layer, (Receiver ID)

[ 15.280157] pcieport 0001:00:00.0: device [10de:22d8] error status/mask=00040000/04400000

[ 15.280160] pcieport 0001:00:00.0: [18] MalfTLP (First)

[ 15.280163] pcieport 0001:00:00.0: AER: TLP Header: 4a008001 01000004 00000028 72040000

[ 15.280274] pci 0001:01:00.0: AER: can’t recover (no error_detected callback)

A Pcie Protocol analyzer see this transaction as errorless:

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Note that the “Raw Symbol Display” shows same data as the “TLP header” of the bad packet in the AER message.

How can I debug why does Jetson AGX Thor sees this packet as malformed?

3

Is this a custom carrier board?
What PCIe device in use here?

4

hi Wayne,

We are using the standard Thor devkit we bought from C.R.G.

We connected our device through M.2 slot. The device can work up to PCIe Gen 4 but even Gen 1 is reporting the same problem.

The same device was also connect to Orin devkit without issue and is working properly on the PCIe side.

5

Could you share full dmesg and lspci -vvv when issue happened?

6

After further debugging we might have found the root cause :

This is the failing scenario

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image1690×229 93.7 KB
Our PCIe card returns 000 instead of 001 on Attributes. Is there is a way to configure the platform to use “No Snoop bit” = 0?

7

Hi,

We don’t think this issue has anything to do with Snoop bit.

Memory read request 1 DW(4 bytes) is sent from Tegra to EP.

EP is sending completion response of size 1DW (4 bytes), but byte count(outstanding bytes) is set to 4 bytes, it should be 0.

I believe this is the reason for malformed TLP error, you need to check why the endpoint side is sending byte count as 4 instead of 0.