2011/12/1 Kumar Gala <ga...@kernel.crashing.org>: > > On Dec 1, 2011, at 3:57 AM, Jean-Michel Hautbois wrote: > >> Hi, >> >> I have a P2020 CPU (powerpc) and I compiled it with two different defconfigs. >> The first one is a SMP, 2 cores, launched with the "nosmp" kernel >> parameter, the other one is an UP kernel. >> >> My driver behaviour is not the same whether launching one or the >> other. It is hard to explain more precisely, as it deals only with >> ioctl which only does ioread32/iowrite32 on a PCIe device. >> But I can tell that it never works the same way when UP (not working >> correctly), or SMP "nosmp" (working) or even SMP (not working). >> >> AFAIK, the "nosmp" parameter should tell the kernel to act the same is >> if it is an UP kernel, and it disables IO APIC, which is not an issue >> in my case. >> >> Can you think about anything that would explain it, or would help me >> debugging it ? > > This is a bit odd, hard to say w/o more details on what exactly your code is > trying to do and wait the failure is.
I understand that it is difficult to give more details, but the driver is not mine, and I can't give all the code associated. > The larger differences between SMP & UP build would be setting of memory > attribute for cache coherency. In UP case we don't set it. > > Between SMP 'nosmp' and SMP 'on' cases you seem like you're hitting some > locking condition. > > Guessing your running into a timing & locking issue that you're getting lucky > on the SMP 'nosmp' case such that it just happens to work. Any idea on how to debug this ? I am using a 2.6.35 kernel. Thanks, JM _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
