I.MX6DL Frequent restart!

[tommyduan]

      Recently the customer returned three machines, the main problem is that the machine is start for a period of time to restart frequently!I look at the LOG information, and it's all the following:

1、Unable to handle kernel paging request at virtual address，Internal error: Oops: 5 [#1] PREEMPT SMP

2、Unhandled fault: alignment exception，Internal error: : 1 [#1] PREEMPT SMP

3、Oops - undefined instruction: 0 [#1] PREEMPT SM

How do I analyze it? What are the possible causes?

oot@sabresd_6dq:/ # [ 59.237256] Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP
[ 59.244333] Modules linked in: ext3 jbd ext2 atmel_mxt_ts gpio_env_ctl rotate_swicth gpio_keys evdev mxc_asrc scsi_wait_scan ipcomp6 xfrm6_tunnel mip6 tunnel6 esp6 ah6 l
[ 59.281122] CPU: 1 Not tainted (3.0.35 #48)
[ 59.285689] PC is at tick_nohz_restart_sched_tick+0x19c/0x1ec
[ 59.291457] LR is at tick_nohz_restart_sched_tick+0x184/0x1ec
[ 59.297224] pc : [<c01857d8>] lr : [<c01857c0>] psr: 600f0093
[ 59.297234] sp : d0061fb0 ip : ffffffff fp : 00000000
[ 59.308738] r10: c0780f60 r9 : 412fc09a r8 : c28be5b8
[ 59.313979] r7 : 0000000d r6 : c930e680 r5 : 0000000d r4 : c919450f
[ 59.320523] r3 : 00989680 r2 : 00000000 r1 : 00000002 r0 : c28be5b8
[ 59.327071] Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 59.334486] Control: 10c53c7d Table: 219cc04a DAC: 00000015
[ 59.340247]
[ 59.340252] PC: 0xc0185758:
[ 59.344543] 5758 e588305c e1a05007 e5887084 ebffcdd9 e1c825d0 e59fa0b0 e1c821f0 e1c821f8
[ 59.352890] 5778 ea00000a e1c801d0 ebfffcac e3500000 0a00001d e28d0008 ebffe41f e59d4008
[ 59.361232] 5798 e59d500c e1a00004 e1a01005 ebfffd43 e1ca60d0 e1a02004 e1a03005 e1a00008
[ 59.369576] 57b8 e1cd60f0 ebffcde5 e598104c e3a02000 e3510002 1affffea e1c861d8 e1a00008
[ 59.377918] 57d8 e1c841d0 e58d1004 e1a03007 e1a02006 e0544006 e0c55007 e58d4000 ebffcfa4
[ 59.386262] 57f8 e5983028 e3530000 0affffe1 f1080080 eaffffa0 ebff1d33 eaffffcc c072e778
[ 59.394604] 5818 c01155b8 c076ec50 c071a080 c0780f60 e92d47f0 e1a0a000 e59f50d8 e24dd010
[ 59.402946] 5838 e59f60d4 ebfffa8c e795410a e1a03006 e0834004 e594306c e3530000 1a000002
[ 59.411290]

[ 128.682076] Unhandled fault: alignment exception (0x001) at 0xc6d05d66
[ 128.688652] Internal error: : 1 [#1] PREEMPT SMP
[ 128.693286] Modules linked in: ext3 jbd ext2 atmel_mxt_ts gpio_env_ctl rotate_swicth gpio_keys evdev mxc_asrc scsi_wait_scan ipcomp6 xfrm6_tunnel mip6 tunnel6 esp6 ah6 l
[ 128.730088] CPU: 1 Not tainted (3.0.35 #48)
[ 128.734646] PC is at finish_task_switch+0x64/0xf0
[ 128.739380] LR is at __schedule+0x40c/0x948
[ 128.743582] pc : [<c0149244>] lr : [<c057e8e8>] psr: a00f0013
[ 128.743593] sp : cc0f19d8 ip : c072e778 fp : cc0f19ec
[ 128.755097] r10: cc0e737c r9 : d0043560 r8 : f606bbce
[ 128.760337] r7 : cc0f0000 r6 : 00000000 r5 : 00000000 r4 : c6d05d3a
[ 128.766880] r3 : c6d05d66 r2 : cc0f0000 r1 : d0043560 r0 : cc0e70e0
[ 128.773427] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 128.780582] Control: 10c53c7d Table: 1c01004a DAC: 00000015
[ 128.786343]
[ 128.786347] PC: 0xc01491c4:

[igorpadykov]

Hi tommy

usually errors like "Internal error: Oops " are caused by memory

errors, so one can try to retest memory with ddr test

i.MX6/7 DDR Stress Test Tool V3.00 

and update image with new ddr calibration coefficients found from test,

put them in uboot/board/freescale/mx6sabresd/mx6dlsabresd.cfg

mx6dlsabresd.cfg\mx6sabresd\freescale\board - uboot-imx - i.MX U-Boot 

Best regards
igor
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[tommyduan]

     There is no problem with the stress test, but I find the CPU frequency is reduced by half when the system is restarted, what will happen? This machine was returned by the customer. It was good before. What are the reasons? Upgrading the software again is useless!

[igorpadykov]

one can also check power supplies and clocks using

i.MX6 System Development User’s Guide

https://www.nxp.com/docs/en/user-guide/IMX6DQ6SDLHDG.pdf

Best regards
igor