Re: Possible critical VIA vt82c686a chip bug

From: Yoann Vandoorselaere (yoann@mandrakesoft.com)
Date: Thu Oct 26 2000 - 08:58:21 EST


Vojtech Pavlik <vojtech@suse.cz> writes:

> Hi!
>
> I've found a bug in my VIA SuperSouth (vt82c686a) chip (ISA bridge
> revision 0x12, silicon rev CD) on my FIC VA-503A rev 1.2:
>
> When there is heavy disk activity (several tars running concurrently on
> UDMA66 drive, or tar'ing from one UDMA66 drive to another over two
> channels), the system time, namely gettimeofday() goes crazy - now and
> then it advances the time about 1:20 for a fraction of a second and then
> changes back to normal time.
>
> This causes X to blank the screen when it should not,

Really strange, I'm getting exactly the same problem on a machine
with the same chipset...

This is an athlon 750 machine, with scsi and ide a disk...
I've tryed to see where the problem was comming from for age
( the problem is what you describe and it happen after some time
  (1 to 24 hour, it depend) and often while or after heavy I/O...
   the only fix is to reboot the machine. )

[...]

> Now I'd like to know if I have a faulty chip, faulty motherboard or
> whether this problem exists in more chips as well.

I've changed my motherboard thinking it was a default of it.
it is not.

> If anyone owning a motherboard with the vt82c686a chip (VIA with UDMA66
> and audio), could test this, I'd appreciate that.

I've this kind of motherboard without audio.

> Attached is a patch that makes the problems go away by reprogramming the
> chip in the problematic case.

I'll try it ASAP, then do a feedback.

-- 
		-- Yoann http://www.mandrakesoft.com/~yoann/
I worry about my child and the Internet all the time, even though she's too 
young to have logged on yet. Here's what I worry about. I worry that 10 or 15 
years from now, she will come to me and say 'Daddy, where were you when they 
took freedom of the press away from the Internet?'  -- Mike Godwin
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