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Date:      Thu, 2 Jul 1998 09:07:54 +0200 (MET DST)
From:      Nick Hibma <nick.hibma@jrc.it>
To:        FreeBSD hackers mailing list <hackers@FreeBSD.ORG>
Subject:   Console driver (was: Problems with irq 9(2)?)
Message-ID:  <Pine.GSO.3.95q.980702085902.16968d-100000@elect8>
In-Reply-To: <359A95A3.7188625A@est.is>

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Seeing the message below I just wanted to post a quick remark about the
console driver in 2.2.1 (and looking at the source code in syscons.c
this is still in there in 3.0-SNAP):

Start a utility like top and move the mouse. Wildly. You'll see that the
CPU usage goes up to 20 percent on an AMD K6-166. A bit much for a
mouse, isn't it, even if the mouse is made by Microsoft. :-) 

The CPU usage comes from:

#if 1 
    while (!(inb(crtc_addr+6) & 0x08)) /* wait for vertical retrace */ ;
#endif

Isn't there a way to check in which vertical line the graphical
processor is working and then do a tsleep until it arrives at line
number max-2 and _then_ start to do this idle loop?

Or, much better, use an int routine called by the vertical retrace that
is mentioned in the message below.

Or, maybe I should stick my head in a bucket of water and not pose
problems that do not need to be solved.

Nick



    > > Does anybody know if there are problems with interrupt blocking
    > > when using interrupt 9(2)?  I am having problems with my token
    > > ring card getting into a user blocked interrupt state and cannot
    > > figure out what to do.  This is really screwing up my token
    > > ring driver development.
    > > 
    > > Any ideas?
    > I am not sure what is going on, but, IRQ 9/2 is often used by vga
    > adapters, if you have ISA vga adapter then the trouble can be orginated
    > there. Vga cards used IRQ2/9 for some retrace call.
    > 
    > Þórður Ívarsson
    > thivars@est.is
    > 
    > To Unsubscribe: send mail to majordomo@FreeBSD.org
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    > 

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