Re: Serial lockup during smp boot [Sarge]
Hello.
On 06/10/05 02:24, Svein Seldal wrote:
> Hi.
>
> I'm running getty. Still, if I remove the getty on ttyS0, the result
> remains the same. The lockup occurs somewhere after init has started (as
> previously) and remains until init 2 is run (when the syslogd/klogd
> kicks in).
>
> I am willing to bet on interrupt problems. As it seems, 16 bytes is
> exactly the size of the HW FIFO of the motherboard. An input character
> triggers the serial interrupt handler, which in turn discoveres that
> there is more data to be transmitted and starts the uart tx. However,
> the mechanism for filling the FIFO when it becomes empty again, seems to
> fail. - But this is only my educated guess / theory.
>
> BTW /proc/interrupts looks like this:
> CPU0 CPU1
> 4: 368 0 IO-APIC-edge serial
>
> Another strange behaviour is that I've seen console output during the
> 16-byte-output-per-input-character period that are normal. I can for
> example sit and press space slowly and see the 16 byte progress. But
> then suddenly the "e100: eth0: e100_watchdog: link up, 100Mbps,
> full-duplex" message shoots out at once!
Did you try to disable this e100? Not to load the module.
> But I have to keep pressing a
> key in the serial console to continue the "normal" boot sequence.
>
> Is there some settings, like APIC or similar, to the kernel, than can be
> used to control how the interrupts are handled?
I know the following places to play with:
- BIOS settings for "PnP OS installed": enable or disable
- Kernel load parameters: acpi_irq_balance, acpi_irq_nobalance, pci=
{usepirqmask, routeirq, etc}... See your
/usr/src/linux/Documentation/kernel-parameters.txt
- Driver initialization and load order. Unfortunately, a good text
regarding this issue is Russian, but you may try Babel.
http://www.citforum.ru/open_source/hard_irq/
A.L.
>
>
> Svein
>
>
> Alexey Lobanov wrote:
>
>> Hello.
>>
>> Two ideas.
>>
>> 1. What program is bound to ttyS0 in inittab? *getty? Nothing? What if
>> to change this (something to nothing or vice versa)?
>>
>> 2. Damned IBM PC interrupts? It may be deja vue, but it seems me that I
>> had same effect in Novell server 10 years ago; the reason was incorrect
>> combination of interrupts in multiple ISA network cards.
>> /proc/interrupts, dmesg?
>>
>> Alexey
>>
>> On 05/10/05 22:35, Svein Seldal wrote:
>>
>>
>>> Hi.
>>>
>>> I have some strange problems during boot of my system:
>>>
>>> I'm running stable (Sarge) with kernel-image-2.6.7-2-686 plus ditto-smp.
>>> I have a Intel machine with a Intel P4 (family 15, model 4) @3GHz. I
>>> have 1G of memory. My SATA HDD's are running software RAID-1 with LVM
>>> (but that's probably irrelevant of this error).
>>>
>>> I'm running serial console as the main console. Hence this line is found
>>> in by grub config: "kernel /vmlinuz-2.6.8-2-686-smp
>>> root=/dev/mapper/System-Root vga=0x31A console=ttyS0,38400 ro"
>>>
>>> If I boot my -smp kernel with this config, the serial console output
>>> (and boot process) locks up after a while. It boots the kernel, starts
>>> userspace apps as expected. It locks up approx. when its doing EXT3FS
>>> mounts. The machine is then apparently dead, nothing more happens.
>>> However, if I then type any charater in my serial console, it will then
>>> output the next 16 bytes of the serial console output. Press a key, and
>>> new 16 charaters from the console output are retured. And it will keep
>>> on doing this until init 2 is run (apparently until the syslogd and
>>> klogd are started)
>>>
>>> This behaviour is not observed when I use the tty0 as console, neither
>>> when I boot the non-smp kernel. Nor does it lockup on shutdown.
>>>
>>> Does anyone know about this "feature"? Is this something to submit a
>>> bugreport about?
>>>
>>>
>>> Regards,
>>> Svein Seldal
>>>
>>>
>
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