Why does Red Hat Enterprise Linux 4 hang when using shpchp (hotplug) operations?

Solution Unverified - Updated -

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:

  1. Power on the machine with an empty SHPC slot.
  2. Load the shpchp driver
  3. 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:

  1. Boot with a card in the SHPC slot
  2. Load the shpchp driver
  3. Power the card down
  4. Replace the card
  5. 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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