Hi, I'm resending this report CC'd to linux-kernel as there was no response on the sparclinux list. I tried 6.2-rc4 and there is no change in behaviour. Reverting the indicated commit still works to fix the problem. On 2022-07-12, Nick Bowler <nbowler@xxxxxxxxxx> wrote: > When using newer kernels on my Ultra 60 with dual 450MHz UltraSPARC-II > CPUs, I noticed that only CPU 0 comes up, while older kernels (including > 4.7) are working fine with both CPUs. > > I bisected the failure to this commit: > > 9b2f753ec23710aa32c0d837d2499db92fe9115b is the first bad commit > commit 9b2f753ec23710aa32c0d837d2499db92fe9115b > Author: Atish Patra <atish.patra@xxxxxxxxxx> > Date: Thu Sep 15 14:54:40 2016 -0600 > > sparc64: Fix cpu_possible_mask if nr_cpus is set > > This is a small change that reverts very easily on top of 5.18: there is > just one trivial conflict. Once reverted, both CPUs work again. > > Maybe this is related to the fact that the CPUs on this system are > numbered CPU0 and CPU2 (there is no CPU1)? > > Here is /proc/cpuinfo on a working kernel: > > % cat /proc/cpuinfo > cpu : TI UltraSparc II (BlackBird) > fpu : UltraSparc II integrated FPU > pmu : ultra12 > prom : OBP 3.23.1 1999/07/16 12:08 > type : sun4u > ncpus probed : 2 > ncpus active : 2 > D$ parity tl1 : 0 > I$ parity tl1 : 0 > cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis > Cpu0ClkTck : 000000001ad31b4f > Cpu2ClkTck : 000000001ad31b4f > MMU Type : Spitfire > MMU PGSZs : 8K,64K,512K,4MB > State: > CPU0: online > CPU2: online > > And on a broken kernel: > > % cat /proc/cpuinfo > cpu : TI UltraSparc II (BlackBird) > fpu : UltraSparc II integrated FPU > pmu : ultra12 > prom : OBP 3.23.1 1999/07/16 12:08 > type : sun4u > ncpus probed : 2 > ncpus active : 1 > D$ parity tl1 : 0 > I$ parity tl1 : 0 > cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis > Cpu0ClkTck : 000000001ad31861 > MMU Type : Spitfire > MMU PGSZs : 8K,64K,512K,4MB > State: > CPU0: online > > Let me know if you need any more info. > > Thanks, > Nick
