Re: OMAP3: enabling CPU idle leads to panic

[Kevin Hilman <khilman@deeprootsystems.com>]

Sergey Lapin <slapinid@gmail.com> writes:

> I use PM branch merged with linux-omap branch. 

Not sure what this means.  PM branch is already based at linux-omap
master branch.  You'll need to be more specific, ideally with commit
IDs.

> A board is custom, so I can't bisect this problem (and I don't know
> latest working revision).
>
> It seems that's because missing clock domain somewhere,
>
>
> [16515.695617] Unable to handle kernel NULL pointer dereference at
> virtual address 00000020
> [16515.703735] pgd = c0004000
> [16515.706481] [00000020] *pgd=00000000
> [16515.710083] Internal error: Oops: 5 [#1] PREEMPT
> [16515.714721] last sysfs file:
> [16515.717712] Modules linked in:
> [16515.720794] CPU: 0    Not tainted  (2.6.32-rc8-07113-g318afc6 #110)
> [16515.727111] PC is at pwrdm_for_each_clkdm+0x34/0x88
> [16515.731994] LR is at pwrdm_for_each_clkdm+0x24/0x88
> [16515.736907] pc : [<c003b5c0>]    lr : [<c003b5b0>]    psr: 600000d3
> [16515.736938] sp : c03f3f68  ip : fa004800  fp : 00000000
> [16515.748474] r10: c003e81c  r9 : 411fc082  r8 : 00000000
> [16515.753723] r7 : a00000d3  r6 : 00000000  r5 : 00000004  r4 : 00000001
> [16515.760284] r3 : 00000002  r2 : c03f2000  r1 : 00000001  r0 : 00000000
> [16515.766845] Flags: nZCv  IRQs off  FIQs off  Mode SVC_32  ISA ARM
> Segment kernel
> [16515.774383] Control: 10c5387d  Table: 80004019  DAC: 00000017
> [16515.780151] Process swapper (pid: 0, stack limit = 0xc03f22e8)
> [16515.786010] Stack: (0xc03f3f68 to 0xc03f4000)
> [16515.790405] 3f60:                   c042e4bc 00000003 00000003
> c042e4bc 80026398 411fc082
> [16515.798645] 3f80: 0000001f c003e76c 00000000 c022f284 00271d5a
> 00000000 00000005 0ec00c5c
> [16515.806854] 3fa0: c03f8640 c03f8710 c042dadc c03f8640 c0474d0c
> c022dee8 c03f2000 c042dadc
> [16515.815093] 3fc0: c0027e14 c03f5bd0 80026398 c002f49c c0459fa4
> c0008914 c0008478 00000000
> [16515.823333] 3fe0: 00000000 c0027e18 00000000 10c53c7d c042dbf0
> 80008034 00000000 00000000
> [16515.831573] [<c003b5c0>] (pwrdm_for_each_clkdm+0x34/0x88) from
> [<c003e76c>] (omap3_enter_idle+0xc0/0x15c)
> [16515.841217] [<c003e76c>] (omap3_enter_idle+0xc0/0x15c) from
> [<c022dee8>] (cpuidle_idle_call+0xa4/0x180)
> [16515.850677] [<c022dee8>] (cpuidle_idle_call+0xa4/0x180) from
> [<c002f49c>] (cpu_idle+0x48/0x98)
> [16515.859344] [<c002f49c>] (cpu_idle+0x48/0x98) from [<c0008914>]
> (start_kernel+0x250/0x2a8)
> [16515.867675] [<c0008914>] (start_kernel+0x250/0x2a8) from
> [<80008034>] (0x80008034)
> [16515.875274] Code: e3a06000 e1a05008 e1a04006 ea000002 (e595101c)
> [16515.881530] ---[ end trace f0a89c74ea639f01 ]---
> [16515.886230] Kernel panic - not syncing: Attempted to kill the idle task!
>
>
> addr2line -e vmlinux c003b5c0
> /home/slapin/linux-omap-my-2.6.git/arch/arm/mach-omap2/powerdomain.c:452
> It is in function
> int pwrdm_for_each_clkdm(), where pwrdm is NULL.
> farther investigations found that "core_pwrdm" is defined only for 24xx,
> but I use 3525, and it is being searched.
>
> This is where variable allocated. If I add BUG_ON(!core_pd), it crashes here.
> arch/arm/mach-omap2/cpuidle34xx.c:348:	core_pd = pwrdm_lookup("core_pwrdm");
> Otherwise it crashes the above way. Any ideas on how to fix this?

I think there is still ongoing work on support for the 3525.  I'm
guessing the clock/pwrdm init still needs work for that SoC.

I have no 3525 hardware, but maybe Sanjeev has more details.

Kevin