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IBM-AUSTRIA - PC-HW-Support 30 Aug 1999 |
Video adapter and Token Ring / IRQ2
PROBLEM - If a video adapter is installed in a PS/VP with a Token Ring adapter set to
IRQ2, communication sessions via the Token Ring network may be dropped or the system
will hang while accessing the network.
Machines AFFECTED -
6382 /S, 6384 /D, 6387 /T
CAUSE - The S3 video chip set interrupt on the mother board is also tied to IRQ2/9.
Normally S3 never uses the IRQ2/9. and with BIOS levels greater than 54, the S3 interrupt
is always active low. But if another video adapter is installed in the system and/or the
system video jumper is set to disabled, then the video BIOS for the S3 is not loaded and
the S3 interrupt is left tri-stated. The tri-stated S3 interrupt causes spurious interrupts to
occur on IRQ2/9 especially when the system H/F is being accessed. The result is that a
Token Ring adapter set to IRQ2/9 will lose communication to the network or will hang the
system.
Temporary workaround -
Change the Token Ring adapter interrupt to a setting other than IRQ2/9.
Permanent fix -
A pullup resistor will be added to the S3 interrupt so that it is always at a known state. A
FRU will be released for the mother board that includes the pullup resistor.
Additional Information - Ensure that at least level 54 BIOS is installed in the system.
if the problem does not occur when the mother board video is being used (i.e., remove the
video adapter) and the problem does not occur when the Token Ring adapter interrupt is
moved to something other than IRQ2/9, then it is most likely that the problem exists.
More INFORMATION / HELP is available at the IBM-HelpCenter
Please see the LEGAL - Trademark notice.
Feel free - send a 
for any BUG on this page found - Thank you.