Dual Core AMD 4050e is seen as single core after upgrade to Karmic

Bug #513905 reported by David MENTRÉ on 2010-01-28
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)

Bug Description


I have a dual core AMD 4050e processor. This processor was correctly seen as dual core in Jaunty 64bits. After an upgrade to Karmic 64bits, the processor is seen as single core.

$ uname -a
Linux erha 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 17:01:44 UTC 2009 x86_64 GNU/Linux

$ cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 15
model : 107
model name : AMD Athlon(tm) Dual Core Processor 4050e
stepping : 2
cpu MHz : 1000.000
cache size : 512 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
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 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow up rep_good extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy 3dnowprefetch
bogomips : 2008.74
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 tm stc 100mhzsteps


David MENTRÉ (dmentre) wrote :
Chris Cheney (ccheney) wrote :

If you boot on a Jaunty CD do you still see both CPUs? Did you check in your BIOS to make sure one the CPUs wasn't disabled in there?

David MENTRÉ (dmentre) wrote :

Hello Chris,

I checked into the BIOS: the CPU was correctly seen as having two cores but I enabled ACPI v3.0 (vs. ACPI v1.0 previously) and I enabled APIC (vs. disabled previously). The second core is now seen!!

I'm closing the bug (-> Fix Released).

Sorry for the noise.

Best regards,

Changed in linux (Ubuntu):
status: New → Fix Released
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