	     Open Fabrics Enterprise Distribution (OFED)
		    mthca in OFED 1.2 Release Notes
			  
			   August 2007


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

===============================================================================
1. Overview
===============================================================================
mthca is the low level driver implementation for the following Mellanox Techno-
logies HCAs: InfiniHost, InfiniHost III Ex and InfiniHost III Lx.

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 firmware commands through doorbell page if non-
			  zero (and supported by firmware)
  catas_reset_disable   - disable device reset on a catastrophic event if non-
			  zero


===============================================================================
2. Fixed Bugs
===============================================================================
1.  Allocating many MRs uses many memory pages and causes a kernel oops. (490)
2.  Improved scheduling of kernel QPs in mthca. (542)
3.  Wrong mthca error reporting (e.g., CQ entry for unknown QP bd0406). (394)
4.  Kernel panic on boot when using Hide-DDR FW. (544)
5.  Off-by-one FMR handling can cause memory corruption for mem-free devices.
    (424)
6.  InfiniHost III Lx: Data corruption when working with FMR (Affected ULPs:
    iSER, SRP and Lustre).
7.  RESET to ERROR transition
8.  Set cleaned CQEs back to HW ownership upon cleaning the CQ
9.  (InfiniHost) Posting more than 255 receive Work Requests
10. Error path in mthca_alloc_memfree()
11. The QP state transition RESET->RESET was not allowed
12. Access to MTT and MPT tables on non-cache-coherent CPUs



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

2. If a user level application using 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. In mem-free devices, RC QPs can be created with a maximum of (max_sge - 3)
   entries only.

4. Performance can be degraded due to a wrong BIOS configuration:
   The PCI Express specification requires the BIOS to set the MaxReadReq
   register for each HCA card for maximum performance and stability. 

   If you experience bandwidth performance degradation, try forcing the card to
   behave not according to the PCI Express specification by setting the
   tune_pci=1 module parameter. This tune_pci=1 assignment was the default
   setting in OFED 1.0; therefore, it may have masked performance degradation
   on some systems.

   If tune_pci=1 improves bandwidth, please report the issue to your BIOS
   vendor. Please note that Mellanox Technologies does not recommend using
   tune_pci=1 in production systems: working with tune_pci=1 set is untested
   and is known to trigger instability issues on some platforms.

