[CentOS] FYI - pci_mmcfg_init kernel error after upgrading to 5.6

Mon Apr 25 13:58:47 UTC 2011
Windsor Dave L. (AdP/TEF7.1) <Dave.Windsor at us.bosch.com>

Just thought I'd pass along an error I received this weekend after 
upgrading two servers to 5.6.  Both are HP Proliant DL380 servers 
running 64-bit, but one is a G6 model and one is a G7.  After the 
upgrade and the reboot to the 2.6.18-238.9.1.el5 kernel, both servers 
displayed the following error at boot:
     "pci_mmcfg_init marking 256MB space uncacheable."

Some Googling found me the following link:
     https://partner-bugzilla.redhat.com/show_bug.cgi?id=581933

There are apparently performance implications due to this issue. 
Fortunately, the solution is simple:  just boot with the kernel parameter
     acpi_mcfg_max_pci_bus_num=on

If everyone is already familiar with this, please ignore. :-)

-- 
Best Regards,

Dave Windsor

Robert Bosch LLC
Team Leader, MES Database Infrastructure Group (AdP/TEF7.1)
4421 Highway 81 North
Anderson, SC 29621 USA
www.bosch.us

Tel: 1 (864) 260-8459
Fax: 1 (864) 260-8422
Dave.Windsor at us.bosch.com