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WinDbg COM port problems

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denis....@dna.ie

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Nov 6, 2001, 6:18:25 AM11/6/01
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Hello All

Using the following line in the boot.ini on my computer is having a
strange effect.

multi(0)disk(0)rdisk(1)partition(1)\WINNT="Microsoft Windows 2000
Professional" /fastdetect /DEBUGPORT=COM1 /BAUDRATE=57600

After I boot with this option WinDbg no longer sees COM1
in windows debugger options.
In fact COM1 also dissapears from the device Manager.
If I boot without /DEBUGPORT=COM1 enabled I have no problem
with COM1.

Now this is OK if the machine in question is to be used as the host
for WinDbg as I only use the option /DEBUG and set the other settings
in WinDbg windows debugger options.

However this is the machine I want to use as the target. SO I think
I need to be able to set all options for debugging at the command line
i.e. /DEBUGPORT=COM1 /BAUDRATE=57600.

Any ideas what WinDbg is doing to my system.

Thanks in advance for any help.

Denis
Denis Gleeson

My opinions only.

Carl Woodward

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Nov 6, 2001, 1:06:36 PM11/6/01
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When you make this change to boot.ini you are asking the kernel to reserve
com1 for debugging. In doing so, it is no longer available for use and will
disappear.

This line is fine on the target or debuggee machine. Ensure you do not have
this line for the host or debugging machine or as you say, com1 will
disappear and WinDBG will not see it.

Hope this helps,

Carl


<denis....@dna.ie> wrote in message
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Maxim S. Shatskih

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Nov 6, 2001, 11:25:42 PM11/6/01
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> Using the following line in the boot.ini on my computer is having a
> strange effect.
>
> multi(0)disk(0)rdisk(1)partition(1)\WINNT="Microsoft Windows 2000
> Professional" /fastdetect /DEBUGPORT=COM1 /BAUDRATE=57600
>
> After I boot with this option WinDbg no longer sees COM1
> in windows debugger options.
> In fact COM1 also dissapears from the device Manager.

This is by design.

/DEBUGPORT switch transfers the UART hardware ownership to KD, thus Serial driver cannot access the UART and COM1 device disappears.

Max

Leo Havmøller

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Nov 7, 2001, 7:08:03 AM11/7/01
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<denis....@dna.ie> wrote in message
news:3be7c7db$1...@ni-news.utvinternet.com...

Maybe /CRASHDEBUG in boot.ini can do it.
See http://www.sysinternals.com/ntw2k/info/bootini.shtml

Leo Havmøller.


denis....@dna.ie

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Nov 7, 2001, 5:31:26 PM11/7/01
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Ok Guys

Thanks for the help.
It was my setup of the Host that was causing the problem.

Doing the following on the host is not a good idea.


>> multi(0)disk(0)rdisk(1)partition(1)\WINNT="Microsoft Windows 2000
>> Professional" /fastdetect /DEBUGPORT=COM1 /BAUDRATE=57600

Denis

>This is by design.

> Max


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