Re: Staging branch [substitute availability armhf-linux]

[calnomble--- via "Development of GNU Guix and the GNU System distribution." <guix-devel@gnu.org>]

Hi,

> > LCD output, nothing answering on serial console (@1.5Mbps
> > (uboot speed) or 115.2Kbps (kernel speed, I think)).

Both kernel and u-boot use 1500000 baud.

> Strange, seems that Caliph did manage to get a serial console. Caliph,
> any insight here?

A configuration close to the pinebook-pro-barebones-os configuration worked for
me software-wise (albiet, without LCD output), but there's a few hardware
tweaks that need to be done to get it working. On the mainboard there's two
switches: an eMMC disable switch and a serial output switch. The serial output
switch needs to be set properly to get serial out through the headphone jack.
Nominally you should also disable the internal eMMC if there's anything on it
in order to use Guix's u-boot, but I wasn't able to get the switch to work so I
just removed the eMMC flash. From the log posted earlier, it does look like
that's the case, so it's booting from the factory-default 2017 u-boot with
blobs.

I just realized that the configuration I used had one (significant) change:
agetty needs to be started on /dev/ttyS2, not /dev/ttyS0. I have just submitted
a patch to fix this (https://issues.guix.gnu.org/45997).

To get the LCD up, I used an inferior with linux-libre-pinebook-pro from the
wip-pinebook-pro branch, and included some kernel arguments from janneke that
Mathieu told me about, though I'm unsure how necessary they are with the kernel
patches. I have also heard that disabling CONFIG_ROCKCHIP_CDN_DP on mainline
would work too, but I haven't tested it.

I'll attach a config that should work to bring up serial and the LCD.

Hope this helps.