Red Hat Bugzilla – Bug 174894
AMD X2 not being recognised, not seeing both cores
Last modified: 2015-01-04 17:23:30 EST
Description of problem: According to /proc/cpuinfo my AMD X2 processor is not being recognised and it is only seeing one of teh two cores. Or is this a BIOS problem??? Version-Release number of selected component (if applicable): kernel-2.6.14-1.1737_FC5 How reproducible: 100% Steps to Reproduce: 1. cat /proc/cpuinfo 2. 3. Actual results: processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 35 model name : AMD Hammer Family processor - Model Unknown stepping : 2 cpu MHz : 2412.394 cache size : 1024 KB physical id : 0 siblings : 1 core id : 0 cpu cores : 1 fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow pni lahf_lm bogomips : 4829.88 TLB size : 1024 4K pages clflush size : 64 cache_alignment : 64 address sizes : 40 bits physical, 48 bits virtual power management: ts fid vid ttp Expected results: Additional info:
Does it work if you boot with the SMP kernel?
Its an X86_64. My understanding is that all te x86_64 kernel aer SMP and thats why there isn't a separate smp.x86_64.rpm in Fedora. Am I wrong? Another possibility is that it is just DaveJ's personal kernal builds that are not SMP? I picked up 1737 from his people.redhat.com directory earlier this morning to investigate a different bug.
I checked DaveJ's x86_64 kernel and it does in fact have CONFIG_SMP set, so yes, there is an issue.
I double checked using only download.fedora.redhat.com kernel: kernel-2.6.14-1.1632_FC5 sees 2 cores kernel-2.6.14-1.1735_FC5 does not.
can you attach dmesg's from both working and not working please ?
Created attachment 121804 [details] dmesg from 2.6.14-1.1632_FC5 - sees 2 cores
Created attachment 121805 [details] dmesg from 2.6.14-1.1737_FC5 - sees 1 core The OOPS is a separate problem - see bug #174188
Created attachment 121808 [details] dmesg from 2.6.14-1.1674_FC5 - sees 2 cores
Created attachment 121809 [details] dmesg from 2.6.14-1.1682_FC5 - sees 1 core
You didn't ask, but in case you were hoping, kernel-2.6.14-1.1739_FC5 didn't fix this, or the oops in #174188.
kernel-2.6.14-1.1770_FC5 and still only one cpu core recognized. Is there any news on this bug?
can you attach a dmesg from a kernel rev 1780 or higher ? I changed something wrt hotplug CPUs that may affect this. (And some upstream x86-64 specific fixes also got merged).
Created attachment 122565 [details] dmesg from 2.6.14-1.1783_FC5 - sees 1 core
There's no indication in the BIOS tables that it knows about the other core. Is there an update available you can try ? What board is this ?
Its a MSI K8N-Neo4-Platinum, purchased within the last month. I was wondering if it was a BIOS problem, but how is it that upto kernel-2.6.14-1-1674 the kernel was seeing 2 cores? (see dmesg in 3rd attachment). I'll go looking for BIOS updates...
Yes, my BIOS is old. I have 1.3 and 1.A is the latest. Doing an update is tough as this box has no floppy and I don't have a windows boot disk. Is it really required? I thought Linux mostly ignored the BIOS? ----------------------------------------- Model Version Size Platform BIOS BIOS Date Counter K8N Neo4 Platinum (MS-7125) v. 1.A 356 kb AMD Award BIOS 11/7/2005 1. This is Award BIOS release 2. This BIOS fixes the following problem of the previous version: - Supports Winbond W39V040FB BIOS ROM 3. 2005/11/07 Model Version Size Platform BIOS BIOS Date Counter K8N Neo4 Platinum (MS-7125) v. 1.9 356 kb AMD Award BIOS 9/9/2005 1. This is Award BIOS release 2. This BIOS fixes the following problem of the previous version: - Improves compatilbility problem with some USB 2.0 devices 3. 2005/09/09 Model Version Size Platform BIOS BIOS Date Counter K8N Neo4 Platinum (MS-7125) v. 1.5 356 kb AMD Award BIOS 6/3/2005 1. This is Award BIOS release 2. This BIOS fixes the following problem of the previous version: - Update CPUID. - Update NVMM version to 4.052.08. - Update NVPXE version 2.12. 3. 2005/06/03 Model Version Size Platform BIOS BIOS Date Counter K8N Neo4 Platinum (MS-7125) v. 1.4 361 kb AMD Award BIOS 5/10/2005 1. This is Award BIOS release 2. This BIOS fixes the following problem of the previous version: - Support AMD K8 reversion E stepping CPU. - Update NVPXE version to 2.12. - Update NVMM version to 4.94. - Update SiI3114 RAID ROM version to 5.2.03. - Update CPU ID. 3. 05/10/2005
Or perhaps the 1674 and earlier kernels didn't actually bring up two cores, but /proc/cpuinfo on those kernels knew about the two cores.
The reason it showed up in /proc/cpuinfo on the older kernels is that was showing what the maximum values were (ie, what the CPU could theoretically do), not what was available (what the BIOS had set up). We require the BIOS to set up a number of things before we boot, such as configuring the APICs. This bit of the changelog.. Support AMD K8 reversion E stepping CPU. is what's important. Rev E were the first dual-cores. I'm pretty convinced this will fix your problem. The lack of floppy will be a problem though. Unless it supports booting from usb memory stick (which some newer boards do). You'll still need to find a bootable DOS image though. Aparently a lot of people have success with http://www.freedos.org As this is a hardware problem, there's really nothing more that I can do here. Good luck!
This problem was fixed by updating to MSI BIOS 7125v1A.
excellent! Thanks for the update.