Bug 210446

Summary:	vt(4) vg_vga when switching between virtual consoles there is a 4 second hesitation in graph mode.
Product:	Base System	Reporter:	joeb1
Component:	kern	Assignee:	freebsd-bugs (Nobody) <bugs>
Status:	New ---
Severity:	Affects Many People	CC:	emaste, portmaster, sblachmann
Priority:	---	Keywords:	vt
Version:	CURRENT
Hardware:	Any
OS:	Any

Description joeb1 2016-06-21 21:35:45 UTC

Running 11.0-ALPHA4-i386-20160617-r301975
vt defaults to graph mode.
When switching between virtual consoles there is a 4 second hesitation.
In text mode no hesitation when switching between virtual consoles.
Hardware details follow.

CPU: Intel(R) Celeron(R) CPU 2.66GHz (2660.05-MHz 686-class CPU)
  Origin="GenuineIntel"  Id=0xf41  Family=0xf  Model=0x4  Stepping=1
Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0x441d<SSE3,DTES64,MON,DS_CPL,CNXT-ID,xTPR>
  TSC: P-state invariant
real memory  = 1073741824 (1024 MB)
avail memory = 1023901696 (976 MB)
Event timer "LAPIC" quality 400
ACPI APIC Table: <DELL   3000   >
random: <Software, Yarrow> initialized
ioapic0: Changing APIC ID to 1
ioapic0 <Version 2.0> irqs 0-23 on motherboard
acpi0: <DELL 3000   > on motherboard
acpi0: Power Button (fixed)
cpu0: <ACPI CPU> on acpi0
atrtc0: <AT realtime clock> port 0x70-0x7f irq 8 on acpi0
Event timer "RTC" frequency 32768 Hz quality 0
attimer0: <AT timer> port 0x40-0x5f irq 0 on acpi0
Timecounter "i8254" frequency 1193182 Hz quality 0
Event timer "i8254" frequency 1193182 Hz quality 100
Timecounter "ACPI-fast" frequency 3579545 Hz quality 900
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0
acpi_button0: <Power Button> on acpi0
vgapci0: <VGA-compatible display> port 0xefa8-0xefaf mem 0xe8000000-0xefffffff,0xfeb80000-0xfebfffff irq 16 at device 2.0 on pci0
agp0: <Intel 82865G (865G GMCH) SVGA controller> on vgapci0
agp0: aperture size is 128M, detected 892k stolen memory
vgapci0: Boot video device
ata0: <ATA channel> at channel 0 on atapci0
ata1: <ATA channel> at channel 1 on atapci0
atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
atkbd0: [GIANT-LOCKED]
psm0: <PS/2 Mouse> irq 12 on atkbdc0
psm0: [GIANT-LOCKED]
psm0: model IntelliMouse, device ID 3
orm0: <ISA Option ROMs> at iomem 0xc0000-0xca7ff,0xca800-0xcbfff pnpid ORM0000 on isa0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
Timecounters tick every 1.000 msec
random: unblocking device.

Comment 1 Chris Hutchinson 2017-03-21 01:38:59 UTC

I can also confirm this to be true in:

FreeBSD trump.whitehouse.gov.test 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r314700: Sun Mar 5 09:01:30 PST 2017 root@trump.whitehouse.gov.test:/usr/obj/usr/src/sys/TESTKERN amd64

loader.conf(5):
linux_load="YES"
nvidia-modeset_load="YES

nvidia-driver-375.26_1

Hardware as reported by Xorg:
(II) NVIDIA(0): NVIDIA GPU GeForce GT 730 (GF108) at PCI:1:0:0 (GPU-0)
(--) NVIDIA(0): Memory: 4194304 kBytes
(--) NVIDIA(0): VideoBIOS: 70.08.ae.00.02
(II) NVIDIA(0): Detected PCI Express Link width: 16X
(--) NVIDIA(0):     CRT-1 (boot)
(--) NVIDIA(GPU-0): CRT-1: connected
(--) NVIDIA(GPU-0): CRT-1: 400.0 MHz maximum pixel clock

I also experience some 10 second delay getting to a console after
bailing from X (logging out of X).

HTH

--Chris

Comment 2 Stefan B. 2017-12-04 04:27:30 UTC

I also confirm that bug.

CAUSE:
The setvideomode stuff is unnecessarily called.
Highly annoying, because mode gets reset, with sync stopping, monitor blanking and taking some time to lock in its PLL again.
One reason why I use sc.

HOW TO FIX:
When changing from one vt to another, do NOT do an unnecessary call to setvideomode BIOS function. This is ONLY necessary when switching between X and vts.
Just blit the framebuffer with the contents of the newly selected VT.