mthca in OFED 1.0 Release Notes
===============================

June 2006

Overview
--------
mthca is the low level driver implementation for all Mellanox Technologies HCAs.

mthca Available Parameters
--------------------------
In order to set mthca parameters, add the following line to /etc/modpobe.conf:

	options ib_mthca parameter=<value>

mthca parameters:

- tune_pci	increase PCI burst from the default set by BIOS if nonzero 
- msi		attempt to use MSI if nonzero 
- msi_x		attempt to use MSI-X if nonzero
- fw_cmd_doorbell  post FW commands through doorbell page if nonzero (and
                   supported by FW) 
 

Known Issues
------------
1. UAR size other than 8MB prevents mthca driver loading. The default of UAR
   size is 8MB. If it is changed, the following error message will be logged to
   /var/log/messages upon attempt to load the mthca driver: 
   ib_mthca 0000:04:00.0: Missing UAR, aborting.

2. If a user level application that uses multicast receives a control signal
   in the process of detaching from a multicast group, its QP may remain a 
   member of the multicast group (in HCA). 
   Workaround: Destroy the multicast group after detaching the QP from it.

3. On MemFree devices, RC QPs can be created with a maximum of max_sge-3 entries
   only.

4. mthca misses restoring the following PCI-X/PCI-Express registers at
   reset:
   PCI-X device: PCI-X command register 
   PCI-X bridge: upstream and downstream split transaction registers 
   PCI Express: PCI-Express device control and link control registers.

   This may cause instability and/or bad performance on systems where one of
   these registers is set to a non-default value by BIOS.
   A fix to this issue is already submitted to kernel 2.6.17.
