The IMX6Q chip I selected found that some boards could not find PCIE devices probabilistically；PCIE hardware design is strictly in line with official Checklist.For example：
1.When using PCIe 2.0, we use an external 100MHz crystal oscillator as input if PCIe uses an external clock because the internal PLL output reference jitter does not meet the PCIe 2.0 requirements。
2.PCIe clock differential pair, please use 100 ohm impedance, TX/RX differential pair, please use 85 ohm impedance.
But I found a phenomenon, when I can not find PCIE device board control chip IMX6Q wind gun heating, PCIE device can be found, why can I find PCIE device IMX6Q heating? What are the possible reasons for the failure to find PCIE devices? Please help the gods to solve the problem, very urgent!