bhyve How to retain 80x24 screensize?

PMc · 2026-03-18T17:42:20+0000

Recently the bhyve console was apparently increased from 80x24 to 240x56, which then occupies the entire display or might even be bigger, and is quite annoying when it suddenly zooms over everything else on the screen.

This happens only when using -l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd. It does not happen when using bhyveload, so that option seems to reside somewhere in the sysutils/edk2 port.

Stranger still: my xterms already have "Allow Window Ops" disabled, so it shouldn't even be possible to zoom them from the application - but they do.

Is there a means to get back to the former behaviour (which did probably just not modify the user's xterm)?

Andrey Lanin · 2026-03-18T18:37:38+0000

I confirm, I observe the same behavior

bakul · 2026-03-18T19:08:29+0000

Does adding something like explicitly specifying display width & height help?
-s 11,fbuf,tcp=0.0.0.0:5900,w=640,h=480,wait \
[When I do this I see 80 columns, 30 rows]

MG · 2026-03-18T19:26:56+0000

Is this maybe the same zoom effect as pressing ctrl-shift-+ (numpad)? That zooms the xterm font and adjusts the window size so that the text fits the same.
I have never seen Ctrl -shift-- working correctly. It mostly zooms out to a tiny unreadable font. Disappointing, I like the Xserver-independent xterm zoom function.

PMc · 2026-03-18T20:11:05+0000

bakul said:
Does adding something like explicitly specifying display width & height help?
-s 11,fbuf,tcp=0.0.0.0:5900,w=640,h=480,wait \
[When I do this I see 80 columns, 30 rows]

No, there is no framebuffer configured or used. The console uses com1.

So: on my desktop, in X, I open an xterm.
In this xterm I run ssh to some server on the other side of the planet.
There I log in to that server.
The server carries a number of bhyve guests.
Now I can connect to the serial console of a guest (with cu serial session), and log in to that guest.
Then I can reboot the guest.
And when the EFI startup appears, the xterm (on my side of the planet) changes size.

PMc · 2026-03-18T20:22:55+0000

MG said:
Is this maybe the same zoom effect as pressing ctrl-shift-+ (numpad)?

No. This ctl-shift-+ key as you describe, that changes the font size while leaving the screen size (number of chars horiz x vert) constant.
The bhyve efi boot event leaves the font size constant, but changes the screen size from 80 x 24 chars (or whatever it currently is) to 240 x 56 chars - so that xterm window gets really BIG.

MG said:
That zooms the xterm font and adjusts the window size so that the text fits the same.
I have never seen Ctrl -shift-- working correctly. It mostly zooms out to a tiny unreadable font.

Yes, that just happened here too. I do normally use ctrl + mouse-right-button: that opens a menu with the available font sizes, and that works.

bakul · 2026-03-18T20:31:24+0000

I too ssh into the host running bhyve instances but I run screen(1) on that host. If I cu(1) to the serial modem of a VM in one of screen windows, I have the opposite problem since my screen uses 80x65 windows but the console returns 80x24!

MG · 2026-03-18T20:50:58+0000

PMc said:
No. This ctl-shift-+ key as you describe, that changes the font size while leaving the screen size (number of chars horiz x vert) constant.
The bhyve efi boot event leaves the font size constant, but changes the screen size from 80 x 24 chars (or whatever it currently is) to 240 x 56 chars - so that xterm window gets really BIG.

Yes, that just happened here too. I do normally use ctrl + mouse-right-button: that opens a menu with the available font sizes, and that works.

I can't read the ctrl menus, too small. I think it's the same system as well as the mouse pointer changing above an xterm window and not listening to the host X settings. It feels old, like X11R6 times and before. I like xterm for its speed. Making these old implementations work correctly again would be nice but it has a complicated source.