Ok, I inherited a basic Windows USB driver that handles pushing data across a
couple of bulk pipes. This driver works fine under Win2K, but eventually
crashes XP/SP2 with a page fault error...

Now, this driver takes a large user buffer and chops it up into nice
USB-able sized blocks. It allocates a MDL and then re-uses it over and over
again, freeing it once the entire transfer has been shoved across the bulk
pipe. Never does it try to MmProbeAndLockPages(), which I found odd.. but it
works under Win2K..

So my question is: should I put in MmProbeAndLockPages() for the user
buffer? And if so, before or after IoBuildPartialMdl() (I think before since
the user buffer needs to be resident, right)?

I'm somewhat clueless, so apologies if this is a dim question. I'm reading
all the docs I can get my hands on!

They are mutually exclusive.

MmProbeAndLockPages means - MDL is based on pageable buffer. IoBuildPartialMdl
means - MDL is based on another MDL.

Sorry, these things are mutually exclusive. The third variant is MDL based on
nonpaged buffer - MmBuildMdlForNonPagedPool. Note that this also works for
memory-mapped devices like video framebuffers.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
maxim@storagecraft.com
http://www.storagecraft.com

you might be running out of PTEs. look at MmPrepareMdlForReuse and see if
that applies. the bulkusb sample demonstrates how to use it.

d

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"Ed Averill" <Ed Averill@discussions.microsoft.com> wrote in message
news:7C9E330F-07E8-4A6F-AB67-6E36C2A83635@microsoft.com...

Edward!!!! How the heck are ya!! We are in Minnesota now, where are you?

Gary
glittle@mn.rr.com
gary.g.little@seagate.com

"Ed Averill" wrote: