Q&A: PCIe and Sleep Mode

[#1]

Question:

Did we tested active PCIe components while the Cortex-A9 was in Sleep Mode (suspend to memory)?

Answer:

It's a known issue that PCIe can't support suspend/resume. And can't be built in kernel image if the system want suspend/resume.

I think PCIe will be active while core is in sleep more. Is it different scenario?

No, the pcie core is not active, it is in L2 state after suspend, and it can't resume back to L0 state when system resume is called.

So, DO NOT let pcie do suspend operation right now.

BTW, the tested device:
* INTEL x1 1000M CT network card.

* INTEL iwl wifi cards.

* x1 pcie to usb3.0 card

Yes, this patch had been tested on imx_3.0.35_4.0 release, and would be merged into next 3.0.35 release. TO1.2 is used. We tested the Patch against imx_3.0.35_4.0 release