Hi Hiep, On Thu, Sep 29, 2016 at 1:03 PM, Hiep Cao Minh <cm-h...@jinso.co.jp> wrote: > I'd like to report the issue of the CPU operation. > We tested and found it on Lager board at linux-v4.8-rcx. > > The test procedure is the following: > > Confirmation command: > > # cat /proc/interrupts > CPU0 > 19: 2509 GIC-0 27 Level arch_timer > 21: 0 GIC-0 36 Level e6050000.gpio > 22: 0 GIC-0 37 Level e6051000.gpio > 23: 0 GIC-0 38 Level e6052000.gpio > 24: 0 GIC-0 39 Level e6053000.gpio > 25: 0 GIC-0 40 Level e6054000.gpio > 26: 0 GIC-0 41 Level e6055000.gpio > 27: 23 GIC-0 101 Level e61f0000.thermal > …” > > This issue appears when we changed the SW8-PIN4 of Lager board. > > SW8-PIN4: ON > > + At linux-v4.7: OK (4 cores work together normally). > + At linux-v4.8-rc2: OK (4 cores work together normally). > > SW8-PIN4: OFF > > + At linux-v4.7: -> OK(4 cores work together normally). > + At linux-v4.8-rc2: -> NG(Only 1 core works).
And the kernel prints "Unable to boot CPU%u when MD21 is set", right? > We tried to find out the issued patch and we realize that it happens from > the following patch: > " 043248c Merge tag 'armsoc-dt' of > git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc" The issue you're seeing is due to a combination of commits 5f3bca0db8ac01a7 ("ARM: shmobile: apmu: Add APMU DT support via Enable method") and dc378795156d980c ("ARM: dts: r8a7790: Add APMU nodes"). When debug mode is enabled (SW8-4 = OFF), trying to boot secondary CPUs may lock up the system after a cold boot, depending of boot load version. Hence we explicitly prohibit that. BTW, this has been the case on Koelsch since commit 277efd30cfc72ec2 ("ARM: shmobile: Check r8a7791 MD21 at SMP boot"). Now, does series "[PATCH/RFT 0/4] ARM: shmobile: R-Car Gen2: Allow booting secondary CPU cores in debug mode" (included in all renesas-drivers releases during September) fix it for you? Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds