Lost drives information on insmod ehci

[Stefano Nicolis]

Hello!

I want to see GRUB2's output on a usb serial line.

I was able to achieve my goal on my laptop by following this
<https://www.coreboot.org/GRUB2#On_a_USB_serial_or_USB_debug_adapter> and
this
<https://unix.stackexchange.com/questions/79838/grub-and-usb-serial-support>,
resulting in this list of commands used in grub cli:

*insmod nativedisk #to not lose drive information after insmod *hci
nativedisk ahci
insmod ehci
insmod ohci
insmod uhci
insmod usbserial_ftdi
terminal_output --append serial_usb0
terminal_input --append serial_usb0
terminfo -a serial_usb0 dumb*

The same procedure did not work on my desktop pc, the problem being that
grub loses drives information after doing *insmod ehci*, meaning that an
*ls* after that returns no disks, and thus all the next commands fail,
nothing can be done anymore and I have to reboot.

As you can see above, this problem was fixed on my SATA-based laptop by
using *nativedisk ahci*, this command doesn't work on the desktop pc
because it uses NVMe (pcie) drives, and the *ahci* module is for SATA
drives, not pcie drives.

So my question is, how do I keep GRUB from losing drive information when
insmoding the various *hci modules?

And more importantly, *why* does it happen? Why am I having pcie issues
when trying to use a usb port?

The GRUB's docs page of nativedisk
<https://www.gnu.org/software/grub/manual/grub/grub.html#nativedisk>
doesn't list any parameter that can be used, so I don't even know where the
guy from the second link got the *nativedisk ahci* idea from.

Thanks for your help.