Subject: Re: PCVT
To: NetBSD-current Users <>
From: Hellmuth Michaelis <>
List: current-users
Date: 04/05/1994 11:58:24
From the keyboard of Holger Veit:

[on masking irq's with spltty() while switching vt's]

> The question is why you want to mask interrupts at all during the copy
> process.

Just to prevent another access to the screen (memory) which is currently
being copied. This could be initiated by another keyboard interrupt.

> But why don't you provide a semaphore like 'in_vty_switch', that is toggled
> (in a spltty/splx critical region) for a vt switch and suspend
> kbd queueing, hotkey processing and video write (by pcwrite/term emu/fontload) 
> while this flag is active?

This seems to be the way to go !

Being a bit lazy in the moment, i had hope that someone would point me to a
solution to disable only the keyboard irq, but .... ;-)

Hellmuth Michaelis    HCS Hanseatischer Computerservice GmbH    Hamburg, Europe
                                The crux of the biscuit is the apostrophe. (FZ)