Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Home NTDEV

Before Posting...

Please check out the Community Guidelines in the Announcements and Administration Category.

More Info on Driver Writing and Debugging


The free OSR Learning Library has more than 50 articles on a wide variety of topics about writing and debugging device drivers and Minifilters. From introductory level to advanced. All the articles have been recently reviewed and updated, and are written using the clear and definitive style you've come to expect from OSR over the years.


Check out The OSR Learning Library at: https://www.osr.com/osr-learning-library/


Keyboard filter driver and caps lock light

OSR_Community_UserOSR_Community_User Member Posts: 110,217
Hi,
I have developed a keyboard filter driver for NT that works fine except
that on certain machines
the caps/num/scroll lights do not function once the filter driver is
activated. Hitting the caps lock key,
for instance, will toggle forced capitalization on/off as the caps lock key
is toggled, but the light doesn't
work. I have pruned my filter driver down to pass everything through and
do nothing but attach itself via
IoAttachDeviceToDeviceStack and I get the same results. On most machines
this problem does not
appear.
Any ideas anyone?


thanks,
Greg Dalcher

Comments

  • OSR_Community_UserOSR_Community_User Member Posts: 110,217
    Hi Grigori,
    I found that the culprit was not double checking that IOCTLs
    intercepted were indeed aimed at my
    driver. Once I added this double check and made sure I passed along all
    IOCTLs not aimed at
    my driver, all worked fine. No trouble reported since.


    thanks,
    Greg


    At 02:33 PM 3/1/00 +0200, you wrote:
    >Hi,
    >I have also developed keyboard filter driver, which does nothing but passes
    >all requests through without modifying them. And we also have reports from
    >customers that on some NT Workstations caps/num/scroll lock lights are
    >always turned on. I haven't investigated the problem yet, but maybe you have
    >already found the reasons of this behavior?
    >If it is possible, could you please inform me? And if I will find the way to
    >fix this problem I will certainly inform you.
    >
    >Best regards,
    >Grigori Shpakov
    >
    >
    >> -----Original Message-----
    >> From: Greg Dalcher [SMTP:[email protected]]
    >> Sent: Thursday, February 24, 2000 9:24 AM
    >> To: NT Developers Interest List
    >> Subject: [ntdev] Keyboard filter driver and caps lock light
    >>
    >> Hi,
    >> I have developed a keyboard filter driver for NT that
    >> works fine except
    >> that on certain machines
    >> the caps/num/scroll lights do not function once the filter driver is
    >> activated. Hitting the caps lock key,
    >> for instance, will toggle forced capitalization on/off as the
    >> caps lock key
    >> is toggled, but the light doesn't
    >> work. I have pruned my filter driver down to pass everything
    >> through and
    >> do nothing but attach itself via
    >> IoAttachDeviceToDeviceStack and I get the same results. On
    >> most machines
    >> this problem does not
    >> appear.
    >> Any ideas anyone?
    >>
    >>
    >> thanks,
    >> Greg Dalcher
    >>
    >
Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. Sign in or register to get started.

Upcoming OSR Seminars
OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!
Kernel Debugging 13-17 May 2024 Live, Online
Developing Minifilters 1-5 Apr 2024 Live, Online
Internals & Software Drivers 11-15 Mar 2024 Live, Online
Writing WDF Drivers 20-24 May 2024 Live, Online