Bug#690727: linux-image-3.2.0-3-686-pae: user space serial console messages held back on HS20 blade until qla2xxx is loaded

[Ferenc Wagner <wferi@niif.hu>]

Ben Hutchings <ben@decadent.org.uk> writes:

> On Tue, 2012-10-16 at 20:44 +0200, Ferenc Wagner wrote:
> 
>> This is an issue on IBM HS20 blades with serial over LAN console.  In short,
>> kernel messages get through all right, but user space messages are buffered
>> until the qla2xxx FC HBA driver module is loaded.  Everything is right if I
>> reverse the order of the two console parameters, making /dev/console refer
>> to the tty0 virtual console.  For debugging, I made the following changes:
>
> Please test Linux 3.5 (as packaged in experimental) or 3.6.

I tried the same in another IBM Bladecenter with slightly different
parts and firmware versions.  There loading qla2xxx does not fix the
user space console output.  Even worse (on a virtual console):

(initramfs) cat /proc/tty/driver/serial
[  225.538801] BUG: unable to handle kernel NULL pointer dereference at 0000009d
[  225.542505] IP: [<c11d15a1>] tty_ldisc_try+0xe/0x37
[  225.542505] *pdpt = 00000000376f8001 *pde = 0000000000000000
[  225.642256] Oops: 0000 [#1] SMP

and the machine freezes here (sometimes after printing two lines only).
Maybe http://thread.gmane.org/gmane.linux.kernel/1101432/focus=1303356?

On the other hand:
(initramfs) setserial -g /dev/ttyS0
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
(initramfs) cat /proc/tty/driver/serial
serinfo:1.0 driver revision:
0: uart:16550A port:000003F8 irq:4 tx:0 rx:0 DSR|CD
1: uart:16550A port:000002F8 irq:3 tx:0 rx:0 CTS|DSR|CD
2: uart:unknown port:000003E8 irq:4
3: uart:unknown port:000003E8 irq:3

But setserial -g /dev/ttyS1 or S2 or S3 does not help like this.

(initramfs) echo hello >/dev/ttyS0

waits for 30 seconds then returns without printing anything.

(initramfs) echo '<2>hello' >/dev/kmsg

does not print to the serial console either, only to the VC (command
line: console=ttyS0,19200n8r console=tty0 loglevel=3 break=top).

User space console output appears on this machine after starting udev,
but I haven't yet found out which module does this.
-- 
Regards,
Feri.