Clearing device buffers from Dispatch Clean up

NTDEV
1

Dear Experts,

I am developing a USB functional driver. In my driver I am using
asynchronous IO in Dispatch R/W.

When read operation is going on, my device buffers are filled with data. Now
if I close the application Dispatch clean will be invoked. Then I wanted to
clear out the data from the device buffers from Dispatch clean, as I am
doing in Dispatch Read.

Now my problem is can I save the Read IRP pointer in Dispatch read and use
it in Dispatch clean to create a virtual read operation?

Or is there any other method to read the data from Dispatch Clean?

Regards,

Ramya

2

I’m confused. When you wrote “my device buffers are filled with data”
did you mean ‘buffers on the physical device’ or ‘buffers associated
with READ IRPs’, or ‘some internal intermediate buffers associated with
your driver used for copying data as part of a read operation’?

By ‘clear out the device buffers’ do you mean that you intend zero fill
data buffers AFTER you complete a READ IRP? Depending on what exactly
you are talking about here that might not be a good idea.

The bulkusb sample in the DDK shows how to manage async R/W operations
and Cleanup operations.

From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ramya Desai
Sent: Tuesday, January 24, 2006 12:50 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Clearing device buffers from Dispatch Clean up

Dear Experts,

I am developing a USB functional driver. In my driver I am using
asynchronous IO in Dispatch R/W.

When read operation is going on, my device buffers are filled with data.
Now if I close the application Dispatch clean will be invoked. Then I
wanted to clear out the data from the device buffers from Dispatch
clean, as I am doing in Dispatch Read.

Now my problem is can I save the Read IRP pointer in Dispatch read and
use it in Dispatch clean to create a virtual read operation?

Or is there any other method to read the data from Dispatch Clean?

Regards,

Ramya

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