zfsloader: messy output on Dell iDrac serial console

[Julian Elischer]

running on *some* Dell servers the serial console looks messed up at
the time of the FreeBSD menu.
it looks like it's dropping (or adding? but that's less likely)
characters.

 |  5. [K]ernel: kernel (1 of 2)           |  .- .                    -.
 |  6. Configure Boot [O]ptions...         |2  --| y/       -.      
-/`   -o/
 |137. Select Boot [E]nvironment...        | `:`                 
`:`         ::/sy++:.
 |                                         H|     .-- `--.     -- 
/6H`:                          :`
 |                                         | .---.....----.

IS there an RTS/CTS input we should be attending to?

I will add that some of the other modules (e.g. the mfi raid setup
section) also get affected,
so it's not just a bug in our code.

[Daniel Braniss]

running on *some* Dell servers the serial console looks messed up at the time of the FreeBSD menu.
it looks like it's dropping (or adding? but that's less likely) characters.
| 5. [K]ernel: kernel (1 of 2) | .- . -.
| 6. Configure Boot [O]ptions... |2 --| y/ -. -/` -o/
|137. Select Boot [E]nvironment... | `:` `:` ::/sy++:.
| H| .-- `--. -- /6H`: :`
| | .---.....----.
IS there an RTS/CTS input we should be attending to?
I will add that some of the other modules (e.g. the mfi raid setup section) also get affected,
so it's not just a bug in our code.

I’m using Serial-Over-LAN via ipmi/drac and am noticing this too on a Dell C6220,
don’t know when this started though, It’s only recently that I’m working on
this kind of hosts. It drives the xterm/rxvt crazy, but it’s only the output from the
boot/loader, once the kernel takes over, all is back to normal. the serial speed is
set to 115200, but changing it as far as i remember did not help. will try lowering soon.
I had to disable the menu to get some sense of the output, and usually have to hit ^B to remove most of the
garbage.

[bob prohaska]

Post by Julian Elischer
running on *some* Dell servers the serial console looks messed up at
the time of the FreeBSD menu.
it looks like it's dropping (or adding? but that's less likely)
characters.
??|?? 5. [K]ernel: kernel (1 of 2)???????????????????? |?? .- .?????????????????????????????????????? -.
??|?? 6. Configure Boot [O]ptions...???????????????? |2?? --| y/???????????? -.????????????

Scrambled console output has shown up on a Pi3 under what might be called
overload conditions, things like make -j8 buildworld and running of stress2's
default test suite. It doesn't seem to be a serial issue in that case.

Hard to believe you're seeing something related, but my $.02 anyway.

bob prohaska