Overlays Source

#1

Hi,

I am running mainline uboot & kernel (5.4.x) and am having issues “finding” my nvme device. I am pretty confident I have all the correct drivers in the kernel, howver if I cat /proc/device-tree/pcie@f8000000/status I get a response of "disabled’ which I believe is because I dont have an overlay enabling it.

I am running Alpine Linux hence I am unable to apt install rockpi4-dtbo and even if I could there is no guarentee they would work as I believe they are for a 4.x kernel.

Is the source available for the overlay files so I can potentially compile and test them and investigate getting them to work with Alpine?

#2

Hi,
pcie is not enabled in mainline for Rock Pi 4 yet.

You can try to use this patch from Armbian to rebuild your device tree in Alpine or as a clue to build your own overlay file if there is a support for overlays in Alpine.

And here you can find gen2 overlay if you are adventurous enough to use it (not supported officially on rk3399).

1 Like
#3

Well certainly explains why the PCIe NVMe drive isnt showing up.

I will investigate the armbian patch, thanks.

Correct me if I am wrong but gen1 vs gen2 is more about throughput then compatibility isnt it? Devices should be backwards compatible?

#4

Well…, devices using it must be “hardware compatible” to support used frequencies.

When rk3399 was first introduced it claimed to support gen2 speeds in the pcie controller but after some time the datasheet was corrected to state that it is a gen1 device.

Using it with gen2 works (and I also have an installation, which is not critical, that uses it) but there probably must have been a reason why Rockchip degraded the claim of supported capabilities in the datasheet.

That’s why in both Radxa’s BSP and Armbian gen2 is not enabled by default but there is an overlay that allows enabling it if you know what you are doing :slight_smile:

#5

I managed to get the SSD to show up but seems to be really inconsistent, I think it may be a power issue but not sure.

Based on dmesg it seems to be reltated to a device tree lookup for voltages and when its working I get multiple entries in cat /sys/kernel/debug/regulator/regulator_summary for f8000000.pcie and when it doesnt work I get a gen1 timeout and no regulator entry.

Anyone have any ideas?