Class key in registry

NTDEV
1

Hi,

I am interested in knowing how the registry’s
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4D36E968-E325-11CE-BFC1-08002BE10318}\xxxx\MatchingDeviceId
is supposed to be set for a VDD.
(4D36E968-E325-11CE-BFC1-08002BE10318 is the DISLPAY
class)

Whats the significance of this key?

-Zeeshan

Yahoo! Mail - PC Magazine Editors’ Choice 2005
http://mail.yahoo.com

2

You don’t set this key, the OS is responsible for it. If you create a new
class in your INF file, the system will create a key for you there.
Basically, you should never directly manipulate things under Class.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
Remove StopSpam from the email to reply

“Zeeshan Razzaque” wrote in message
news:xxxxx@ntdev…
> Hi,
>
> I am interested in knowing how the registry’s
> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4D36E968-E325-11CE-BFC1-08002BE10318}\xxxx\MatchingDeviceId
> is supposed to be set for a VDD.
> (4D36E968-E325-11CE-BFC1-08002BE10318 is the DISLPAY
> class)
>
> Whats the significance of this key?
>
> -Zeeshan
>
>
>
> __________________________________
> Yahoo! Mail - PC Magazine Editors’ Choice 2005
> http://mail.yahoo.com
>

3

> Basically, you should never directly manipulate things under Class.
…with one notable exclusion: when you add/delete components of
REG_MULTI_SZ values of “UpperFilters” and/or “LowerFilters”.

Thing is, even FLG_ADDREG_APPEND | FLG_ADDREG_TYPE_MULTI_SZ = 0x10008 does
not fit the bill.

Let’s say, you want your upper filter myCdUpper to be below redbook, not
above; if AddReg in your INF uses 0x10008, you get

redbook\0myCdUpper\0\0

so your filter sits above, not below redbook.

You have to play with multistring values manually to set the registry value
to

myCdUpper\0<what_was_there_before_i_came>

.

See AddFilterDriver(…) function and friends in

C:\WINDDK\3790.1830\src\storage\filters\addfilter\addfilter.c

for details.

Regards,
Alex Shvedov

----- Original Message -----
From: “Don Burn”
Newsgroups: ntdev
To: “Windows System Software Devs Interest List”
Sent: Sunday, September 25, 2005 8:43 AM
Subject: Re:[ntdev] Class key in registry

> You don’t set this key, the OS is responsible for it. If you create a new
> class in your INF file, the system will create a key for you there.
> Basically, you should never directly manipulate things under Class.
>
>
> –
> Don Burn (MVP, Windows DDK)
> Windows 2k/XP/2k3 Filesystem and Driver Consulting
> Remove StopSpam from the email to reply
>
>
>
> “Zeeshan Razzaque” wrote in message
> news:xxxxx@ntdev…
>> Hi,
>>
>> I am interested in knowing how the registry’s
>> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4D36E968-E325-11CE-BFC1-08002BE10318}\xxxx\MatchingDeviceId
>> is supposed to be set for a VDD.
>> (4D36E968-E325-11CE-BFC1-08002BE10318 is the DISLPAY
>> class)
>>
>> Whats the significance of this key?
>>
>> -Zeeshan
>>
>>
>>
>> __________________________________
>> Yahoo! Mail - PC Magazine Editors’ Choice 2005
>> http://mail.yahoo.com
>>
>
>
>
> —
> Questions? First check the Kernel Driver FAQ at
> http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@bellsouth.net
> To unsubscribe send a blank email to xxxxx@lists.osr.com
></what_was_there_before_i_came>