Re: [Kgdb-bugreport] [PATCH] Kill kgdb_serial

[George Anzinger <george@mvista.com>]

Tom Rini wrote:
> On Wed, Mar 03, 2004 at 04:51:06PM +0100, Pavel Machek wrote:
> 
>>Hi!
>>
>>
>>>>>More precisely:
>>>>>http://lkml.org/lkml/2004/2/11/224
>>>>
>>>>Well, that just says Andrew does not care too much. I think that
>>>>having both serial and ethernet support *is* good idea after all... I
>>>>have few machines here, some of them do not have serial, and some of
>>>>them do not have supported ethernet. It would be nice to use same
>>>>kernel on all of them. Also distribution wants to have "debugging
>>>>kernel", but does _not_ want to have 10 of them.
>>>
>>>But unless I'm missing something, supporting eth or 8250 at all times
>>>doesn't work right now anyhow, as eth if available will always take over.
>>
>>Well, that can be fixed. [Probably if kgdbeth= is not passed, ethernet
>>interface should not take over. So user selects which one should be
>>used by either passing kgdbeth or kgdb8250. That means that 8250
>>should not be initialized until user passes kgdb8250=... not sure how
>>you'll like that].
> 
> 
> At this point, I'm going to give up on killing kgdb_serial, and pass
> along some comments from David Woodhouse on IRC as well (I was talking
> about this issue, and the init/main.c change):
> (Tartarus == me, dwmw2 == David Woodhouse)
> 
> <Tartarus> dwmw2, the problem is how do you deal with all of the
> possibilities of i/o (8250, kgdboe, or other serial) and do you allow
> for passing 'gdb' on the command line to result in kgdb not being dropped
> into?  You can always break in later on of course
> <dwmw2> parse command line early for 'gdb=' argument specifying which
> i/o device to use. init kgdb core early. init each i/o device as early
> as possible for that i/o device. Start the selected i/o device as soon
> as it becomes available.
> <dwmw2> just like console could, if we looked for console= a little bit
> earlier. (forget all the earlyconsole shite, it's not necessary)
> <dwmw2> Tartarrus, do the __early_setup() thing to replace __setup() for
> selected args. We can use that for console= too.
> <dwmw2> since 'console=' on the command line _already_ remembers its
> arguments, and starts to use the offending device as soon as it gets
> registered with register_console().
> <Tartarus> dwmw2, __early_setup() ?
> <dwmw2> See __setup("gdb=", gdb_setup_func);
> <dwmw2> Replace with __early_setup(...)
> <Tartarus> where is __early_setup ?
> <dwmw2> before we normally parse the command line
> <dwmw2> in my head
> 
> So perhaps someone can take these ideas and fix both problems... :)
> (I've got some other stuff I need to work on today).

Well, __early_setup could mean the fist setup call and if so that would be what 
we do in -mm.  It is done by putting the code in the first module ld sees, not 
nice, but it works.


> 

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml