When I try and do pkg help install or man 2 open on the serial console of a SandyBridge box, it doesn't seem to want to render the manpages with *roff.
If I do it on the VGA redirected console over IPMI, it works.
The processes appear to be stuck in ttydcd state.
(please disregard the build date; the svn revision is the part of interest -- the last merge I did with my github fork was about 8 days ago)
% uname -a
FreeBSD mina3008.localdomain 11.0-CURRENT FreeBSD 11.0-CURRENT #0 a32b4d9(master): Thu Jul 17 02:58:38 PDT 2014 email@example.com:/usr/obj/scratch/freebsd/sys/GENERIC amd64
% pkg help install
load: 0.00 cmd: more 1361 [ttydcd] 1.23r 0.00u 0.00s 0% 2636k
load: 0.00 cmd: more 1361 [ttydcd] 1.47r 0.00u 0.00s 0% 2636k
load: 0.00 cmd: more 1361 [ttydcd] 1.71r 0.00u 0.00s 0% 2636k
load: 0.00 cmd: more 1361 [ttydcd] 1.91r 0.00u 0.00s 0% 2636k
q^C% man 2 open
load: 0.00 cmd: more 1374 [ttydcd] 1.47r 0.00u 0.00s 0% 2636k
I just tried to do sysctl kern.conftxt | less and I ran into the same issue, so it looks like output paging in general is broken on the serial console.
Happens with syscons too, so I guess vt isn't necessarily to blame.
Peter H pointed me in the right direction (I missed this section in UPDATING):
The uart(4) driver has been changed with respect to its handling
of the low-level console. Previously the uart(4) driver prevented
any process from changing the baudrate or the CLOCAL and HUPCL
control flags. By removing the restrictions, operators can make
changes to the serial console port without having to reboot.
However, when getty(8) is started on the serial device that is
associated with the low-level console, a misconfigured terminal
line in /etc/ttys will now have a real impact.
Before upgrading the kernel, make sure that /etc/ttys has the
serial console device configured as 3wire without baudrate to
preserve the previous behaviour. E.g:
ttyu0 "/usr/libexec/getty 3wire" vt100 on secure