On Thu, 2015-01-01 at 00:52 -0800, James Bottomley wrote:
> On Wed, 2014-12-31 at 23:56 -0500, Peter Hurley wrote:
> > On 12/31/2014 08:33 PM, James Bottomley wrote:
> > > On Tue, 2014-11-11 at 20:13 +0100, Helge Deller wrote:
> > >> 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
> >
> > I apologize that I did not see this email back in November; I was having some
> > email trouble at the time.
> >
> > >> 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
> > >
> > > I confirm this behaviour on the Mako system as well. In my case, 3.18
> > > so royally screws up the serial port that even a power cycle won't
> > > recover the console connection to the MP (a sort of parisc equivalent of
> > > a BMC) and I have to go down to the machine room to physically yank the
> > > power from the system to power down the MP and get the console back.
> > > I've added a cc to linux-serial. It looks like there are 20 non merge
> > > commits between 3.17 and 3.18. I'm betting because of the MP problem
> > > it's got to be somewhere in the serial driver:
> > >
> > > cd92208 tty: serial: 8250_mtk: Fix quot calculation
> > > 716e115 serial: 8250_pci: remove rts_n override from Baytrail quirk
> > > 1ede7dc serial: 8250: Add Quark X1000 to 8250_pci.c
> > > 9137568 tty: serial: 8250_core: remove UART_IER_RDI in
> > > serial8250_stop_rx()
> >
> >
> > > 59b3e89 tty: serial: 8250_core: use the ->line argument as a hint in
> > > serial8250_find_match_or_unused()
> > ^^^^^^^^^
> > This commit would be my first guess, but a complete dmesg up to boot
> > failure would be helpful in narrowing down the problem. There are about
> > 50 ways to initialize the 8250 port (which is part of the problem).
>
> Well, bisection says it's not this one. Unfortunately, we crap out at
> this one:
>
> ae14a79 tty: serial: 8250_core: provide a function to export
> uart_8250_port
>
> CC drivers/tty/serial/8250/8250_core.o
> drivers/tty/serial/8250/8250_core.c: In function 'serial8250_ioctl':
> drivers/tty/serial/8250/8250_core.c:2857: error: 'TIOCSRS485' undeclared
> (first use in this function)
> drivers/tty/serial/8250/8250_core.c:2857: error: (Each undeclared
> identifier is reported only once
> drivers/tty/serial/8250/8250_core.c:2857: error: for each function it
> appears in.)
> drivers/tty/serial/8250/8250_core.c:2858: error: implicit declaration of
> function 'copy_from_user'
> drivers/tty/serial/8250/8250_core.c:2869: error: 'TIOCGRS485' undeclared
> (first use in this function)
> drivers/tty/serial/8250/8250_core.c:2870: error: implicit declaration of
> function 'copy_to_user'
> make[4]: *** [drivers/tty/serial/8250/8250_core.o] Error 1
> make[3]: *** [drivers/tty/serial/8250] Error 2
> make[2]: *** [drivers/tty/serial] Error 2
> make[1]: *** [drivers/tty] Error 2
>
> I'll work out how to fix it in the morning ... but really, having a
> bisectable tree is supposed to be the first rule of a maintainer.
OK, I managed to bisect the rest of the tree compensating for the build
failure. This is the failing commit (cc's added):
commit 2f2dafe77df2c78e189a9fa6b1879dffd06ae5a1
Author: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
Date: Mon Sep 1 20:49:43 2014 +0530
serial: serial_core.c: printk replacement
I've confirmed by reverting against 3.19-rc2 and the system boots again.
This looks like a symptom of underlying problems within the dev_ print
helper accessors, so I'll dig further, but we'll need this reverted in
the meantime.
James
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
