usb bulk transfer driver crash
- From: "jasonlue" <jasonlue@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 2 Jun 2005 14:18:05 -0700
Hi, all,
I create a usb bulk transfer driver based on the example in DDK. It normally
works greate except:
1. When driver has to split a big data into small transfers usbd can accept
(4K on my computer). I continue the next small transfers in
ReadWriteCompletion just like the example. After transfering a big file
around 500M for 1M packet each to eventually split into 4k's in driver, the
driver crashes. I understand most likely it's caused by virtual memory
mapping. Where on Completion function (running DISPATCH_LEVEL), access to
user memory is not safe. (although I create a internal MDL to map to that
memory). Am I correct here?
I rewote my code to split the packet from user mode in Read/Write Irp
function and set a loop there to complete until all data are transfered.
Surprisingly enough, the driver still crashes. What could be possible reason
here?
Anybody writing usb bulk drivers, how do you handle big data and split them?
thanks for all comments.
.
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