serial8250: too much work for irq36

Hi there,

I am currently working on Poky on an embedded PPC system.

I am experiencing a "serial8250: too much work for irq36" problem around 50-75% times I try to boot.

What I was thinking to do is

1. Reduce printk lines
2. Check if there is any fix about this error on Linux source files update

The error I am observing is this one::

serial8250_interrupt: 8544 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8881 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8881 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8880 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250_interrupt: 8881 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
INFO: rcu_sched self-detected stall on CPU
	3: (1 GPs behind) idle=f9f/140000000000001/0 softirq=0/0 fqs=1699 
INFO: rcu_sched detected stalls on CPUs/tasks:
	0: (1 GPs behind) idle=965/140000000000001/0 softirq=0/0 fqs=1699 
	3: (1 GPs behind) idle=f9f/140000000000001/0 softirq=0/0 fqs=1699 
	(detected by 1, t=52517 jiffies, g=91, c=90, q=161)
Task dump for CPU 0:
(agetty)        R running      0  1915      1 0x00000084
Call Trace:
[ed0079a0] [c005b408] update_cfs_rq_blocked_load+0xb8/0x1c0 (unreliable)
[ed007a60] [00000211] 0x211
Task dump for CPU 3:
systemd-journal R running      0   957      1 0x00000004
Call Trace:
rcu_sched kthread starved for 50818 jiffies!
	 (t=52529 jiffies g=91 c=90 q=161)
rcu_sched kthread starved for 50831 jiffies!
Task dump for CPU 0:
(agetty)        R running      0  1915      1 0x00000084
Call Trace:
[ed0079a0] [c005b408] update_cfs_rq_blocked_load+0xb8/0x1c0 (unreliable)
[ed007a60] [00000211] 0x211
Task dump for CPU 3:
systemd-journal R running      0   957      1 0x00000004
Call Trace:
[e9ee9b80] [c007f948] rcu_dump_cpu_stacks+0xa8/0x100 (unreliable)
[e9ee9ba0] [c008386c] rcu_check_callbacks+0x4fc/0x7b0
[e9ee9c10] [c008725c] update_process_times+0x3c/0x70
[e9ee9c20] [c009afb8] tick_sched_timer+0x68/0xe0
[e9ee9c50] [c00880b4] __run_hrtimer.isra.34+0x54/0xf0
[e9ee9c70] [c00889b8] hrtimer_interrupt+0x118/0x330
[e9ee9ce0] [c0009658] __timer_interrupt+0xa8/0x1a0
[e9ee9d00] [c0009980] timer_interrupt+0xb0/0xe0
[e9ee9d20] [c000f7e0] ret_from_except+0x0/0x18
--- interrupt: 901 at smp_call_function_many+0x2a0/0x300
    LR = smp_call_function_many+0x270/0x300
[e9ee9de0] [c00a033c] smp_call_function_many+0x24c/0x300 (unreliable)
[e9ee9e20] [c00177cc] flush_tlb_mm+0x9c/0xa0
[e9ee9e40] [c00f8dd8] tlb_flush_mmu_tlbonly.part.86+0x18/0x90
[e9ee9e50] [c00f8f54] tlb_flush_mmu+0x24/0x40
[e9ee9e60] [c00f8f88] tlb_finish_mmu+0x18/0x70
[e9ee9e70] [c00fee00] unmap_region+0xc0/0x140
[e9ee9ef0] [c01013ec] do_munmap+0x26c/0x430
[e9ee9f20] [c01015e8] vm_munmap+0x38/0x60
[e9ee9f40] [c000f130] ret_from_syscall+0x0/0x3c
--- interrupt: c01 at 0x201842fc
    LR = 0x20117090
serial8250_interrupt: 8544 callbacks suppressed
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36
serial8250: too much work for irq36

2 things spring to mind

1. 1. There were 2 chips used for serial interfaces: the 8250, which was the old/crappy/slow one; the 16550 which superceded it. Get on a 16550 if you can.
2. In the old days it used be possible to set interrupts as level or edge triggered.

If you can set your interrupts to edge triggered, that will probably solve it. I take it this is a museum piece, with a heavily obsolete 8250? AFAIK, they haven't been made since the 1980s.

Originally Posted by business_kid 2 things spring to mind 1. There were 2 chips used for serial interfaces: the 8250, which was the old/crappy/slow one; the 16550 which superceded it. Get on a 16550 if you can. In the old days it used be possible to set interrupts as level or edge triggered. If you can set your interrupts to edge triggered, that will probably solve it. I take it this is a museum piece, with a heavily obsolete 8250? AFAIK, they haven't been made since the 1980s.

Hi, thank you for your reply!

Could you please describe me which option shall be enabled or disabled? I found something about 8250 in the kernel config menu but I am not sure about them

Originally Posted by JuventusFC Hi, thank you for your reply! Could you please describe me which option shall be enabled or disabled? I found something about 8250 in the kernel config menu but I am not sure about them

On that much information, neither am I!