https://alexforencich.com/wiki/ 2026-04-22T09:19:27+00:00 https://alexforencich.com/wiki/ https://alexforencich.com/wiki/_media/wiki/dokuwiki.svg text/html 2020-04-29T06:00:28+00:00 Anonymous (anonymous@undisclosed.example.com) https://alexforencich.com/wiki/en/pcie/disable-fatal?rev=1588140028&do=diff PCIe Disable Fatal Error Reporting When loading a new configuration on a PCIe-connected FPGA, the device can fall off the bus. This is usually no problem at all so long as drivers are properly unloaded, etc. before reconfiguring the FPGA. However, some systems complain bitterly when the device falls off the bus, such as a Dell R540: text/html 2020-04-29T06:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://alexforencich.com/wiki/en/pcie/ext-tag-control?rev=1588140000&do=diff PCIe Extended Tag Control This script uses setpci to enable or disable PCI express extended tags on the specified device. #!/bin/bash dev=$1 en=$2 if [ -z "$dev" ]; then echo "Error: no device specified" exit 1 fi if [ -z "$en" ]; then echo "Error: must specify operation" exit 1 fi if [ ! -e "/sys/bus/pci/devices/$dev" ]; then dev="0000:$dev" fi if [ ! -e "/sys/bus/pci/devices/$dev" ]; then echo "Error: device $dev not found" exit 1 fi ctrl=$(setpci -s $dev C… text/html 2020-04-29T06:01:03+00:00 Anonymous (anonymous@undisclosed.example.com) https://alexforencich.com/wiki/en/pcie/force-gen2?rev=1588140063&do=diff PCIe Force Gen 2 This script uses setpci to force a device to fall back from gen 3 to gen 2 link rate. This can be useful when using a PCIe protocol analyzer that does not support PCIe gen 3. It may be necessary to run this script on the switch or root port upstream of the device. text/html 2020-04-29T05:59:41+00:00 Anonymous (anonymous@undisclosed.example.com) https://alexforencich.com/wiki/en/pcie/hot-reset-linux?rev=1588139981&do=diff PCIe Hot Reset on Linux Resets in PCI express are a bit complex. There are two main types of resets - conventional reset, and function-level reset. There are also two types of conventional resets, fundamental resets and non-fundamental resets. See the PCI express specification for all of the details. text/html 2020-04-29T06:01:21+00:00 Anonymous (anonymous@undisclosed.example.com) https://alexforencich.com/wiki/en/pcie/set-speed?rev=1588140081&do=diff PCIe Set Speed This script uses setpci to change a device's target link speed. This can be useful when using a PCIe protocol analyzer that does not support PCIe gen 3. It can also be helpful for testing a device at a lower bandwidth. #!/bin/bash dev=$1 speed=$2 if [ -z "$dev" ]; then echo "Error: no device specified" exit 1 fi if [ ! -e "/sys/bus/pci/devices/$dev" ]; then dev="0000:$dev" fi if [ ! -e "/sys/bus/pci/devices/$dev" ]; then echo "Error: device $dev not foun… text/html 2019-08-04T08:05:22+00:00 Anonymous (anonymous@undisclosed.example.com) https://alexforencich.com/wiki/en/pcie/start?rev=1564905922&do=diff PCI Express Notes Here is a compendium of useful tips and tricks I have discovered pertaining to PCI express. PCIe Hot Reset on LinuxPCIe Extended Tag ControlPCIe Disable Fatal Error ReportingPCIe Force Gen 2PCIe Set Speed