While testing kernel 3.18-rc4 I'm facing a problem with serial console.
I'm seeing at bootup this message:
[ 17.724000] console [ttyS0] disabled
after that it's just hanging.
It seems as if ttyS0 is somehow being reprogrammed which then disturbs the
serial ports on the receiver side (in my case a HP PCI Diva Serial [GSP] Multiport UART).
Any idea what changed between 3.17 and 3.18 which have caused this behavior ?
Full log below.
Helge
serial driver: drivers/tty/serial/8250/8250_pci.c
PCI info:
00:04.1 Serial controller: Hewlett-Packard Company Diva Serial [GSP] Multiport UART (rev 03) (prog-if 02 [16550])
Subsystem: Hewlett-Packard Company Device 1283
Flags: medium devsel, IRQ 70
Memory at ffffffff80000000 (32-bit, non-prefetchable) [size=4K]
I/O ports at 0040 [size=64]
Capabilities: [48] Power Management version 2
Kernel driver in use: serial
dmesg after bootup:
[ 17.708000] Serial: 8250/16550 driver, 8 ports, IRQ sharing enabled
[ 17.724000] serial 0000:00:04.1: enabling device (0142 -> 0143)
[ 17.724000] console [ttyS0] disabled
[ 17.880000] serial 0000:00:04.1: ttyS0 at MMIO 0xffffffff80000000 (irq = 70, base_baud = 115200) is a 16550A
[ 17.996000] console [ttyS0] enabled
[ 38.888000] INFO: rcu_sched detected stalls on CPUs/tasks: { 3} (detected by 1, t=5252 jiffies, g=-290, c=-291, q=2)
[ 38.888000] Task dump for CPU 3:
[ 38.888000] swapper/0 R running task 0 1 0 0x00000004
[ 38.888000] Backtrace:
[ 38.888000] [<0000000040200848>] vprintk_emit+0x570/0x5f8
[ 38.888000] [<0000000040200bdc>] printk+0x64/0x78
[ 38.888000] [<0000000040201fc0>] register_console+0x438/0x550
[ 38.888000] [<0000000040688bb8>] uart_add_one_port+0x400/0x5d0
[ 38.888000] [<000000004068e6d4>] serial8250_register_8250_port+0x3e4/0x448
[ 38.888000] [<0000000040695f44>] pciserial_init_ports+0x22c/0x2c8
[ 38.888000] [<0000000040696628>] pciserial_init_one+0x250/0x2e0
[ 38.888000] [<00000000405f3880>] pci_device_probe+0xb0/0x150
[ 38.888000] [<00000000406a8244>] driver_probe_device+0x204/0x570
[ 38.888000] [<00000000406a8728>] __driver_attach+0xe0/0x158
[ 38.888000] [<00000000406a4558>] bus_for_each_dev+0xd0/0x128
[ 38.888000] [<00000000406a76f8>] driver_attach+0x48/0x60
[ 38.888000] [<00000000406a6de8>] bus_add_driver+0x268/0x460
[ 38.888000] [<00000000406a915c>] driver_register+0x124/0x1d0
[ 38.888000] [<00000000405f336c>] __pci_register_driver+0x64/0x78
[ 38.888000] [<00000000401375e4>] serial_pci_driver_init+0x44/0x58
[ 59.084000] timer_interrupt(CPU 3): delayed! cycles 85EBC4C7D rem 2BAF83 next/now 2765C08677/276594D6F4
[ 59.140000] bootconsole [ttyB0] disabled
[ 59.144000] serial 0000:00:04.1: ttyS1 at MMIO 0xffffffff80000008 (irq = 70, base_baud = 115200) is a 16450
[ 59.164000] serial 0000:00:04.1: ttyS2 at MMIO 0xffffffff80000010 (irq = 70, base_baud = 115200) is a 16550A
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