Description of problem: I have an Intel G965 based motherboard from Asus named P5B-VM whose BIOS needs a MTRR workaround from recent mainline kernels to be able to boot when I install more than 4GiB of memory. I reported this problem for Fedora 8 as #438960 and it was promptly fixed, but now I need to run RHEL 5 to do some work related stuff on my machine and the update kernel 2.6.18-53.1.14.el5 exhibits the same problems as fedora kernels did before kernel-2.6.24.4-64.fc8 Version-Release number of selected component (if applicable): kernel-2.6.18-53.1.14.el5 How reproducible: always Steps to Reproduce: 1. get my motherboard 2. install more than 4GiB of memory 3. try to boot Actual results: the boot grinds to a halt, as predicted by the upstream fix author (referenced in the original bug). Expected results: a regular boot, as exhibited when 4GiB memory or less is installed. Additional info: as stated above, the fix from 2.6.25 backported to the 2.6.24 based fedora kernel is available from https://bugzilla.redhat.com/show_bug.cgi?id=438960 as well as pointers to the relevant commits to the upstream tree. If you need help testing proposed patches to verify that it solves the problem, I'm more than willing to help out with that.
Created attachment 305161 [details] mtrr change from bug 438960 patch from bug 438960 comment#17 by djones. This is the take2 patch that went into fedora 8.
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I am advised. However, my guess is that my hardware is not all that exotic, the fix is nicely contained and suitable for backporting IMO so integrating it into the RHEL5 kernel would be something that RH would want to do. After all, the next customer that hits this problem might not be able to point you to the relevant fix and if you proactively address this issue now, your own time and customers time might be saved later on. Well well, in a couple of years we'll have a RH release based on a later upstream kernel (and I will have new hardware) and inte meantime I'll be able to use Fedora and live with the mismatch between our development and production environment.