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User-Agent: Mozilla/4.75 [ja] (WinNT; U)

Description of problem:
Many insmod and rmmod qla1280 driver causes hanging up of system.
We discovered it on "shutdown and reboot" test. We have qla12160,
on kernel 2.4.3-12smp.

How reproducible:
Sometimes

Steps to Reproduce:
1.Make shellscript like below:
    #!/bin/sh
    while [ 1 ]; do
        insmod qla1280
        if [ $? != 0 ]; then
            exit 1
        fi
        rmmod qla1280
        if [ $? != 0 ]; then
            exit 1
        fi
    done
2.Run it.
3.Wait for 24 hr or so. Very rare case, but you must see this.


Actual Results:  Stopped at the message below:

Loading qla1280 module
qla1x160:Surported Device Found
              VIO=1077 DID=1216 SSVID=1077 SSDID=7
SCSI(0)=Determing if RISC is loaded ...
SCSI(0)=Verifying chip....


Expected Results:  The shellscript works good forever.


Additional info:

The stopped function is in qla1280_debounce_register() called from qla_chip_diag().
    do
    {
        ret = RD_REG_WORD(addr);
        ret2 = RD_REG_WORD(addr);
    } while (ret != ret2);
This might be infinite loop. So, we guess this is just a issue of read/write register timing.
if we add usleep() function into this loop, the problem won't appear no more.
And more, if we compile the module without -O2 switch, hard to reproduce it.

We can see this issue on both up/smp kernel.