Bug 23953

Summary: setserial changes irq setting for irq 9
Product: [Retired] Red Hat Linux Reporter: Bill Gorder <w.gorder>
Component: setserialAssignee: Tim Waugh <twaugh>
Status: CLOSED CURRENTRELEASE QA Contact: David Lawrence <dkl>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.0   
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2001-10-19 13:03:04 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description Bill Gorder 2001-01-13 16:39:24 UTC 
I have a PCI modem (US Robotics model 3CP5610A).  The bus walk places 
the modem at port 0xd400 and irq 9 (from /proc/pci).  I use setserial 
to set the port and irq values, but setserial changes my irq 9 request 
to irq 2.  The man page for setserial has the statement, "On AT class 
machines, IRQ2 is seen as IRQ9 and Linux will interpret it in this 
way."  This may be fine for AT class machines, but this is disaster for 
PCI - irq 2 is assigned to the process controller for cascade 
interrupts.

This technique for configuring PCI modems is documented at 
http://www.o2.net/~gromitkc/3cp5610.txt with a pointer to this page 
from Red Hat.
Comment 1 Tim Waugh 2001-10-19 13:02:59 UTC 
What exactly are the bad effects that you see?
Comment 2 Tim Waugh 2001-10-19 13:36:49 UTC 
Apprently this works fine in 7.1.  Closing.