I thought I was gaining an understanding of how drivers get loaded in
Windows 10, and I have successfully written a few now, but recently I have
been trying to resolve a problem with the native OS driver(s) for the
dvdrom in my laptop and discovered that information gets written to the
registry that is not in the cdrom.inf file. For instance the FriendlyName,
that shows up in device manager and the registry is not in that file and a
LowerFilter (tdcmdpst.sys) shows up in the registry under
HKLM\System\CurrentControlSet\Enum\IDE(device specific keys) that is also
not listed in the INF file along with a lot of other registry info. If I
delete any of this info, such as the lower filter, and then reboot, it just
gets added (from somewhere) again. What other files, besides the driver INF
file, does Windows use to fill in the registry for the device? Does the
firmware in the device load some of this info? The only file for the
device that shows up in the boot log is cdrom.sys (which doesn’t load). I
have a problem with the device not working once windows loads (I can boot
from it without any problem) and one of the recommended fixes is to remove
any upper or lower filters. And as I said if I delete the lower filter from
the registry it just gets added back when I reboot.
Randy
FriendlyName can be populated from the device if the driver reads it and sets the property. For filters, I would suspect another INF is floating around the system. The definitive answer should be to look in the setupapi logs and see what got applied.
d
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of Randy Lewis
Sent: Friday, April 29, 2016 3:05 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] What files does Windows 10 use when loading native drivers for a dvdrom device?
I thought I was gaining an understanding of how drivers get loaded in Windows 10, and I have successfully written a few now, but recently I have been trying to resolve a problem with the native OS driver(s) for the dvdrom in my laptop and discovered that information gets written to the registry that is not in the cdrom.inf file. For instance the FriendlyName, that shows up in device manager and the registry is not in that file and a LowerFilter (tdcmdpst.sys) shows up in the registry under HKLM\System\CurrentControlSet\Enum\IDE(device specific keys) that is also not listed in the INF file along with a lot of other registry info. If I delete any of this info, such as the lower filter, and then reboot, it just gets added (from somewhere) again. What other files, besides the driver INF file, does Windows use to fill in the registry for the device? Does the firmware in the device load some of this info? The only file for the device that shows up in the boot log is cdrom.sys (which doesn’t load). I have a problem with the device not working once windows loads (I can boot from it without any problem) and one of the recommended fixes is to remove any upper or lower filters. And as I said if I delete the lower filter from the registry it just gets added back when I reboot.
Randy
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Randy Lewis wrote:
I thought I was gaining an understanding of how drivers get loaded in
Windows 10, and I have successfully written a few now, but recently I
have been trying to resolve a problem with the native OS driver(s) for
the dvdrom in my laptop and discovered that information gets written
to the registry that is not in the cdrom.inf file. For instance the
FriendlyName, that shows up in device manager and the registry is not
in that file and a LowerFilter (tdcmdpst.sys) shows up in the registry
under HKLM\System\CurrentControlSet\Enum\IDE(device specific keys)
that is also not listed in the INF file…
Remember that, besides device filters, you can also install a class
filter that gets loaded for every device in the device class. These are
named in CurrentControlSet\Control\Class. There might be a class filter
“fixing” things for you.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
Doron and Tim,
Thanks for the quick replies. I didn’t find any indication of a failed install in the setupapi.dev.log file but in an old setupapi.app.log file I found reference to the mysterious LowerFilter “tdcmdpst.sys” file. It’s associated with a Toshiba Disk Creator program. That gave me the idea that the problem might be occurring after the device was installed and during the LowerFilter driver installation associated with the app. I uninstalled the app, which I’ve never used anyway and it was originally installed with Vista (the laptop is old but still works well for what I use it for) so it was probably not compatible with Windows 10. After rebooting, the dvd device is working properly and the LowerFilter no longer shows up in the registry. So am I correct that the device could initially install properly during bootup and then get hosed up by an application that installs later, or have I overlooked something?
Randy
xxxxx@gmail.com wrote:
… After rebooting, the dvd device is working properly and the LowerFilter no longer shows up in the registry. So am I correct that the device could initially install properly during bootup and then get hosed up by an application that installs later, or have I overlooked something?
Absolutely. More accurately, an application that installs a driver later.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
And doesn?t need an inf to do that,it can use standard setupapi apis to add the filter
Sent from my Windows 10 phone
From: Tim Robertsmailto:xxxxx
Sent: Friday, April 29, 2016 6:32 PM
To: Windows System Software Devs Interest Listmailto:xxxxx
Subject: Re: [ntdev] What files does Windows 10 use when loading native drivers for a dvdrom device?
xxxxx@gmail.com wrote:
> … After rebooting, the dvd device is working properly and the LowerFilter no longer shows up in the registry. So am I correct that the device could initially install properly during bootup and then get hosed up by an application that installs later, or have I overlooked something?
Absolutely. More accurately, an application that installs a driver later.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
—
NTDEV is sponsored by OSR
Visit the list online at: http:
MONTHLY seminars on crash dump analysis, WDF, Windows internals and software drivers!
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