can we communicate to a lower driver without IoCallDriver ?

NTDEV
1

While looking at Broadcomm bluetooth (WIDCOMM 5.1 XP) driver I found out that’s the BTKRNL driver only use IoCallDriver for talking to the lower driver (BTWUSB) for the IRP+AF8-MJ+AF8-POWER
and IRP+AF8-MJ+AF8-PNP. so I wonder how it really communicate to the lower driver. major operation are done while using IOCTL to BTKRNL. so im totally lost

I only know the scenario of a driver talking to the lower driver while using IoCallDriver… if someone know how this voodoo can be done I would be happly to know.

Thanks for your helps.

-Nico

2

There are lots of ways if you have control of both drivers. For instance,
the lower driver can register a device interface that the upper driver
queries getting a block of function poiinters. For legacy devices the same
technique has been used for years with calling an IOCTL to the lower driver
and it returning a block of fuction pointers. Finally, you can create
entry points as in a DLL in the lower driver.

For PnP the device interface is the best approach since it is sensitive the
PnP model, where the others can create situations where a driver needs to go
away or stop, but the users of the interface expect things to work.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
Website: http://www.windrvr.com
Blog: http://msmvps.com/blogs/WinDrvr
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“nicolas dirand” wrote in message
news:xxxxx@ntdev…
While looking at Broadcomm bluetooth (WIDCOMM 5.1 XP) driver I found out
that’s the BTKRNL driver only use IoCallDriver for talking to the lower
driver (BTWUSB) for the IRP_MJ_POWER
and IRP_MJ_PNP. so I wonder how it really communicate to the lower driver.
major operation are done while using IOCTL to BTKRNL. so im totally lost

I only know the scenario of a driver talking to the lower driver while using
IoCallDriver… if someone know how this voodoo can be done I would be happly
to know.

Thanks for your helps.

-Nico

3

anti love wrote:

While looking at Broadcomm bluetooth (WIDCOMM 5.1 XP) driver I
found out that’s the BTKRNL driver only use IoCallDriver for talking
to the lower driver (BTWUSB) for the IRP-MJ-POWER and IRP-MJ-PNP.

Why are you trying to reverse engineer Widcomm’s drivers?