Message-ID: <4050FA42.3040006@mvista.com>
Date: Thu, 11 Mar 2004 15:46:10 -0800
From: George Anzinger <george@mvista.com>
Organization: MontaVista Software
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To: Tom Rini <trini@kernel.crashing.org>
CC: "Amit S. Kale" <amitkale@emsyssoft.com>, Pavel Machek <pavel@ucw.cz>,
       Kernel Mailing List <linux-kernel@vger.kernel.org>,
       kgdb-bugreport@lists.sourceforge.net
Subject: Re: [Kgdb-bugreport] [PATCH] Kill kgdb_serial
References: <20040302213901.GF20227@smtp.west.cox.net> <200403031113.02822.amitkale@emsyssoft.com> <20040303151628.GQ20227@smtp.west.cox.net> <200403041011.39467.amitkale@emsyssoft.com> <20040304152729.GC26065@smtp.west.cox.net> <4047B67A.4050609@mvista.com> <20040304231737.GJ26065@smtp.west.cox.net> <4050DB34.8060704@mvista.com> <20040311223321.GL5169@smtp.west.cox.net> <4050EDEE.6050706@mvista.com> <20040311230004.GN5169@smtp.west.cox.net>
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Tom Rini wrote:
> On Thu, Mar 11, 2004 at 02:53:34PM -0800, George Anzinger wrote:
> 
> 
>>Tom Rini wrote:
>>
>>>On Thu, Mar 11, 2004 at 01:33:40PM -0800, George Anzinger wrote:
>>>
>>>>Tom Rini wrote:
>>>>
>>>>>>I am afraid I don't quite understand what he was saying other than 
>>>>>>early init stuff.  On of the problems with trying early init stuff, by 
>>>>>>the way, is that a lot of things depend on having alloc up and that 
>>>>>>happens rather late in the game.
>>>>>
>>>>>I assume you aren't talking about kgdb stuff here (or what would be the
>>>>>point of going so early) but I believe he was talking about allowing for
>>>>>stuff that could be done early, to be done early.
>>>>
>>>>One of the issues with the UART set up is registering the interrupt 
>>>>handler with the kernel.  It will fail if alloc is not up.  The -mm patch 
>>>>does two things with this.  a) It tries every getchar to register the 
>>>>interrupt handler, and b) it has a module init entry to register it.  
>>>>This last will happen late in the bring up and is safe.  a) is there to 
>>>>get it ASAP if you are actually using kgdb during the bring up.
>>>
>>>
>>>There's two ways to look at this.
>>>- All the more reason to acknowledge that the earliest you can safely
>>> get into KGDB is point X, where X is where alloc works, 
>>
>>Just to get ^C to work?  I would rather give it up entirely!
>>
>>> mappings done
>>> if needed, etc, etc, and IFF we change things slightly in kgdboe so
>>> that it can call kgdb_schedule_breakpoint() if it needs to as an
>>> initial break, and handle setting kgdb_serial to the serial driver in
>>> kgdb_arch_init, or something, and remove all of the extra kludges to
>>> get us a few lines / function calls earlier on.
>>>- More and more special cases.
>>
>>How about a command line set up ASAP which calls a driver entry to do the 
>>break. The driver being serial does it NOW, but being some thing that 
>> needs additional resources, just sets a flag to break when it gets them and 
>>returns. Seems rather simple.
> 
> 
> This sounds a lot like what I passed along from dwmw2 a week ago. :)

Must be something wrong here.  We seem to be agreeing :)
> 

-- 
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

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