On 25/04/11 15:44, Windsor Dave L. (AdP/TEF7.1) wrote: > On 4/25/2011 10:26 AM, Johnny Hughes wrote: >> On 04/25/2011 08:58 AM, Windsor Dave L. (AdP/TEF7.1) wrote: >>> 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. :-) >>> >> >> Supposedly this issue is fixed in the 5.6 kernel ... not introduced in it :D >> >> https://bugzilla.redhat.com/show_bug.cgi?id=581933 >> >> However, the advise is good regardless of version of kernel. >> > > > Yes, I saw the reference to RHEL 5.5 in the bug description, but I never > saw the message before the upgrade to CentOS 5.6. Hardware differences, > I guess. The bug description mentions a Dell Precision. > > Best Regards, > > Dave Windsor > I saw and reported the issue during QA for CentOS-5.6. I think it's quite widespread, I saw it on generic Intel-based motherboards. I've not had any issues applying the documented "fix" and have been running that since January.