Problem accessing a buffer in USB stack

hello all

We have a custom built monolithic USB Host controller driver on WINCE
5.0.
When we connect a storage class device the mass-storage class
driver gets loaded and runs it's initializations.
In this process when the partition driver is loaded we happen to get a
buffer pointer for a read request on bulk. When we write to this buffer
in the HCD we get a data abort exception.

We found that
1. the pointer is not NULL
2. MapCallerPtr is called before we get it in the HCD.

Is there any pre-processing that we need to do before we access any
such pointer.
I have already tried LockPages.

please advise.

Shreepad

voidcoder
Tue Nov 28 03:16:05 CST 2006


What buffer size is passed the time it happens? And are
you sure you are writing within this range? Do you also get
an exception if you only write the first byte in the buffer?


shreepad.hardas@gmail.com wrote:
> hello all
>
> We have a custom built monolithic USB Host controller driver on WINCE
> 5.0.
> When we connect a storage class device the mass-storage class
> driver gets loaded and runs it's initializations.
> In this process when the partition driver is loaded we happen to get a
> buffer pointer for a read request on bulk. When we write to this buffer
> in the HCD we get a data abort exception.
>
> We found that
> 1. the pointer is not NULL
> 2. MapCallerPtr is called before we get it in the HCD.
>
> Is there any pre-processing that we need to do before we access any
> such pointer.
> I have already tried LockPages.
>
> please advise.
>
> Shreepad
>

David
Tue Nov 28 16:52:40 CST 2006

Do you know where this address come from? Kernel, Filesys or other
application?
David Liao
<shreepad.hardas@gmail.com> wrote in message
news:1164610633.930783.35110@n67g2000cwd.googlegroups.com...
> hello all
>
> We have a custom built monolithic USB Host controller driver on WINCE
> 5.0.
> When we connect a storage class device the mass-storage class
> driver gets loaded and runs it's initializations.
> In this process when the partition driver is loaded we happen to get a
> buffer pointer for a read request on bulk. When we write to this buffer
> in the HCD we get a data abort exception.
>
> We found that
> 1. the pointer is not NULL
> 2. MapCallerPtr is called before we get it in the HCD.
>
> Is there any pre-processing that we need to do before we access any
> such pointer.
> I have already tried LockPages.
>
> please advise.
>
> Shreepad
>