[openib-general] mthca: switching between MSI-X and MSI mode

[Michael S. Tsirkin]

Hi!
I am trying to enable MSI-X, then disable and enable MSI.
This fails.

~>modprobe ib_mthca msi_x=1
~>rmmod ib_mthca

Works fine

~>modprobe ib_mthca msi=1

The second modprobe fails to get interrupts from the device.
An attempt to fall back to regular interrupts fails as well:

ib_mthca 0000:04:00.0: NOP command failed to generate interrupt (IRQ 201),
aborting.
ib_mthca 0000:04:00.0: Try again with MSI/MSI-X disabled.
ib_mthca 0000:04:00.0: Clearing mask 00000000001f43fe for eqn 2
ib_mthca 0000:04:00.0: Clearing mask 0000000000000400 for eqn 3
ACPI: PCI interrupt for device 0000:04:00.0 disabled
ib_mthca: probe of 0000:04:00.0 failed with error -16

Looks like a linux bug, does it not?

-- 
Michael S. Tsirkin
Staff Engineer, Mellanox Technologies