Why does Red Hat Enterprise Linux 4 hang when using shpchp (hotplug) operations?
Environment
- Red Hat Enterprise Linux 4
- shpchp (hotplug)
Issue
Why does Red Hat Enterprise Linux 4 hang when using shpchp (hotplug) operations?
Resolution
The normal procedure to use hotplug devices is listed below:
- Power on the machine with an empty SHPC slot.
- Load the
shpchp
driver - Insert card into SHPC slot, close latch, switch the power on to the card.
This causes a Red Hat Enterprise Linux 4 system to hang. It has been determined that the power on code calls a function that is labeled as __init
when it is needed after initialization code is done. A patch removing __init
from the function after it is called after boot prevents the int3
from happening and allows shpchp operations to work. The patch will be included in a future update of Red Hat Enterprise Linux version 4.
To avoid this problem:
- Boot with a card in the SHPC slot
- Load the
shpchp
driver - Power the card down
- Replace the card
- Power on the card
If want to disable the shpchp (hotplug), can add the following lines in the file /etc/hotplug/blacklist
pciehp
shpchp
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