explicit refresh?

[Laszlo Ersek]

Hi,

this is a dumb question and it's not appropriate for a development
mailing list, but I couldn't find "grub-user" or "grub-users", so I'll
ask here anyway...

My laptop is connected to my workstation via USB-serial (USB for the
laptop, serial for the workstation). Sometimes, by the time the laptop
comes up and starts "screen", for viewing the serial output from the
workstation, the workstation is already displaying the grub menu.
Occasionally in this case, I can't see anything at all, there's no grub
countdown, the cursor up/down keys do nothing (they certainly don't
refresh the screen), but if I blindly press Enter, then the selected
kernel entry is booted okay (and that kernel does produce serial output,
and takes the LUKS password from serial fine as well).

So, Q1: what could cause the loss of serial output from grub when I
connect to it "too late"?

Q2: when that happens, can I press something like C-r to force a full
serial / screen refresh?

I know that USB-serial adaptors are generally wacky, but this is a
Prolific PL2303 adaptor which is (to my knowlede) usually considered
reliable. Plus, my laptop has no physical RS/232 port (shame on you, all
laptop vendors of today!), so this is the best I can do.

Thanks,
Laszlo