Bug 233356 - vt(4) doesn't support rc.conf parameters saver= or blanktime=
Summary: vt(4) doesn't support rc.conf parameters saver= or blanktime=
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: CURRENT
Hardware: Any Any
: --- Affects Many People
Assignee: freebsd-bugs (Nobody)
URL:
Keywords: vt
Depends on:
Blocks:
 
Reported: 2018-11-20 16:15 UTC by Joe Barbish
Modified: 2024-12-21 16:55 UTC (History)
5 users (show)

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Description Joe Barbish 2018-11-20 16:15:16 UTC 
The vt default console screen driver doesn't support the rc.conf parameters saver=  or  blanktime=. The boot time console messages has this message,

Configuring vt: blanktime screensaver 

But really has no effect.

rc.conf contains saver="warp" & blanktime="900"

If kern.vty=sc in /boot/loader.conf then they work.
Comment 1 Joe Barbish 2018-11-20 16:21:22 UTC 
Same effect in amd64 or i386 systems.
Comment 2 Ed Maste freebsd_committer freebsd_triage 2019-09-16 19:18:04 UTC 
blanktime needs CONS_BLANKTIME to be implemented:
https://github.com/freebsd/freebsd/blob/master/sys/dev/vt/vt_core.c#L2309
Comment 3 Ed Maste freebsd_committer freebsd_triage 2024-05-24 22:17:39 UTC 
Source code link has gone stale, it is supposed to be a link to the unimplemented CONS_BLANKTIME:

	case CONS_BLANKTIME:
		/* XXX */
		return (0);
Comment 4 Nick Date 2024-07-18 21:27:23 UTC 
This issue is still present in 14.1-RELEASE. I spend  lot of time in the console without X running on my affected machine (it is a stationary laptop performing some server functions). I don't want to use sc because it doesn't work with KMS. Are there any plans to fix this?
Comment 5 Guilherme Janczak 2024-12-21 16:55:20 UTC 
This bug caused burn-in on an old laptop I use via remote access. The FreeBSD login prompt was burned onto it after weeks/months continuously on and with the lid closed.

Setting kern.vty=sc in /boot/loader.conf caused the laptop to boot to a blank screen. sc's man page appears to warn against this on UEFI systems, but this laptop is BIOS.

A workaround is to start the xdm (X Display Manager) service on boot, closing the lid will then turn off the screen.