Messages in this thread | | | Date | Sun, 15 Nov 2009 20:18:55 +0000 | From | Alan Cox <> | Subject | Re: consolechars switches tty since 8b92e87 vt: add an event interface |
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> ioctl(3, VIDIOC_G_COMP or VT_ACTIVATE, 0x2) = 0
Switch to VT 2 > ioctl(3, VIDIOC_S_COMP or VT_WAITACTIVE, 0x2) = 0
Wait for VT 2 to activate
> ioctl(3, PIO_UNIMAPCLR, 0x7fff042a0160) = 0 > ioctl(3, PIO_UNIMAP, 0x7fff042a0730) = 0
Set maps
> ioctl(3, VIDIOC_G_COMP or VT_ACTIVATE, 0x1) = 0
Switch back to VT 1
> ioctl(3, VIDIOC_S_COMP or VT_WAITACTIVE, 0x1) = 0
Wait for VT1 to activate.
Nothing odd there, definitely looks like a kernel problem.
> I have one thing to add. It looks like that is not fully deterministic > behavior, at least not at f278a2f^ I'm using now. Occasionally tty > isn't switched. I wasn't aware of this before.
The console switch is asynchronously handled so a race or a bug in the handling of the event wait which is what I suspect would indeed show up that behaviour. X and other apps don't do sudden fast switch and switch backs which would hide such a bug.
> I just booted that f278a2f^ (i.e. 569ec4c) while consolechars were > limited only to console-setup script, but this time tty1 remained on > the screen and I didn't get "INIT: open(/dev/console): Input/output > error" I was seeing before. I'm not sure whether it is relevant here.
The I/O error is a different bug (technically a user space one), but the new behaviour was different, not at all expected and was fixed back to the old sane behaviour.
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