	     Open Fabrics Enterprise Distribution (OFED)
		    mthca in OFED 1.1 Release Notes
			  
			   September 2006


===============================================================================
Table of Contents
===============================================================================
1. Overview
2. New Features
3. Fixed Bugs
4. Known Issues

===============================================================================
1. 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)
  - catas_reset_disable    disable device reset on a catastrophic event if nonzero


===============================================================================
2. New Features
===============================================================================
1. Catastrophic event reset: catastrophic event handling has been expanded
   to include resetting the device. After generating the IB_EVENT_DEVICE_FATAL
   async event, mthca now resets the device (assuming that the
   catas_reset_disable module parameter described above is zero).

   Note that the reset entails removing then adding the device. For the device
   to complete the reset, all user-level applications using device resources
   directly via the user verbs layer must release those resources. Thus, such
   applications should register to receive async events, should detect the
   IBV_EVENT_DEVICE_FATAL event, and should release all resources for that
   device upon receiving such an event.


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3. Fixed Bugs
===============================================================================
1. mthca no longer misses restoring the following PCI-X/PCI Express
   registers after reset:
     o  PCI-X device: PCI-X command register
     o  PCI-X bridge: upstream and downstream split transaction registers
     o  PCI Express: PCI Express device control and link control registers
2. Fence bit is now supported properly.
3. Fixed modify_qp, modify_srq and resize_cq methods to be fully reentrant.

===============================================================================
4. Known Issues
===============================================================================
1. UAR size other than 8MB prevents mthca driver loading. The default 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.

