I have a PCIe connection with Generation 3 and 4 lanes, as can be seen from lspci -vvv | egrep 'LnkSta|LnkCap:
LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L0s L1, Exit Latency L0s <1us, L1 <2us
LnkSta: Speed 8GT/s (ok), Width x4 (ok)
LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete+, EqualizationPhase1+
I want to configure it to Gen2 (speed=5) and then to Gen1 (speed=2.5), and also change the lanes to 2 and 1.
I checked the setpci man but I don't see how to actually find the right configuration parameters to change what I want...
I also found this script that does some configuration, but couldn't make it work.
I'm using Ubuntu20, kernel 5.4.0-42-generic
