iMX6 PCIe gen 2 card compatibility

[tordandersson]

I have done some tests on a PCIe gen 2 based USB3380 card on an IMX6Q-based reference board using the latest mainline kernel with associated net2280 driver.

The only way, at the moment to make it work is to force gen 1 link speed.

Is this common for all gen 2 cards?

Are there fixes or patches available that will make it possible to reenable gen 2?

I guess that this problem is related to Re: i.MX6Q: Re-establishing a PCIe link and errata ERR005184.

BR,

Tord

[igorpadykov]

Hi Tord,

had you tried connection with Sabre reference boards ?

In general this may be related to signal loss due to board material

and layout. One can try to tweak signal strength with IOMUXC GPR8

as described in AN4784 AN4784: PCIe Certification Guide for i.MX 6Dual/6Quad and

i.MX 6Solo/6DualLite - Application Note

Best regards

igor

[fabio_estevam]

Hi Tord,

I think this is topic should be discussed at the PCI mailing list.

Could you please start a thread there so that we can address this issue?

Please run ./scripts/get_maintainer.pl -F drivers/pci/host/pci-imx6.c to know the lists and people to Cc.

Thanks,

Fabio Estevam

[tordandersson]

Thanks Fabio,

I have passed on the question to the linux-pci mailing list and the IMX6 PCI driver's maintainer.

Best regards,

Tord