I inserted a pcie x1 card into the pcie x4 slot,but when i used cmd lspci,there is no thing to found.
So, i has build the kernel and selected the pci bus config, but there is no thing too.
Normally PCIe should just work. An x1 in an x4 slot also should not be a problem. Since there is no mounting bracket with the board I suspect it is difficult on some smaller x1-in-x4-slot setups to make proper contact. You might want to post the “dmesg” content from right after boot with the PCIe card installed (you can use the forum “block quote” icon in the upper right which looks like “</>” to make the long dmesg look better and have a scrollbar).
Do you have any kind of specification on what the PCIe card is to get an idea of what its requirements are?
I have noticed something similar. lspci shows nothing at all. I am assuming it should show some PCI devices.
I have inserted a card with an 8 port EXAR chip, the driver didn’t load so I thought I would just check to see if it was there. lspci shows nothing, no PCI devices at all.
I removed the card, still nothing.
Am I wrong? Are there not PCI devices like I am expecting in the Jetson TX2? Obviously I can’t scan the bus using I/O ports like on an x86 machine.
I will admit , in my case I just installed Jetson 3.2 DP .
Normally there are no PCI devices on the Jetson…some devices you would traditionally see there are wired directly to the memory controller. On a Jetson you won’t even see the PCIe bridge unless something is connected to it.
However, you are correct that something should show up if you have a PCIe card connected, even if there is no driver for the card. There are a few devices (such as an FPGA) which may take time to boot, and if the boot of the device does not occur before the PCIe bus scan on the Jetson, then the device won’t show up…and this would not be a bug.
Some PCIe slots on other devices are hot-plug. The Jetson is not. Thus a detect of something coming online at a later time may show up on a hot-plug capable PCIe slot, but possibly not on the Jetson. Once again, FPGAs come to mind. I don’t know what the EXAR chip is, someone else may have more ideas.
You could try this after boot:
sudo echo 1 > /sys/bus/pci/rescan
This URL might be of interest if this device has some sort of delay causing the problem:
https://devtalk.nvidia.com/default/topic/997845/force-rescan-of-pcie-bus-/?offset=3
Thanks, it didn’t work, but the PCIe device could just be initializing incorrectly. Its and EXAR UART but it is across a PCIe switch so that could be the issue (the switch I mean). The Gen2 Switch may be screwing up.
Anyways, thanks for the reply. Now if I could just find the introduction guide to where the cross compiling tools got placed after the Jetpack installation.
Is there any way to disable ASPM on the PCIe x4?
There is likely a way to disable ASPM, but I couldn’t tell you without some research…it also probably differs depending on L4T release.
Most of the tools for the PC side end up somewhere in “/usr/local/” (executables in “/usr/local/bin” perhaps). I’d suggest going there and looking unless the tools were installed from a regular Ubuntu repository…then they’d be in somewhere like “/usr/bin” for the executables.