Re: USB device detection via query registry information
- From: "Ben Voigt [C++ MVP]" <rbv@xxxxxxxxxxxxx>
- Date: Fri, 5 Sep 2008 09:32:39 -0500
Doron Holan [MSFT] wrote:
WHQL is not a 100% measure of quality across an entire driver, rather
it is a set of tests specifically designed to test very specific
parts of a driver. why is msft reponsible for the crud that FTDI
wrote? serenum and sermouse work as expected on the in box version
of serial, it correctly enforces exclusivity to the port
WHQL is realistically not going to be able to catch all bugs before
shipment, so maybe the answer is for WHQL signing to require a commitment
from the driver developer to participate in the BSOD crash dump program and
issue timely bug fixes (this is usually what is meant by having a "quality"
process in sw development, right?). A public "Wall of BSOD Shame" listing
drivers with known bugs and no fix might also be worth considering. Yes
these things would not come free, but is it important to Microsoft to shed
the reputation for Windows being crash-prone?
d
"Ben Voigt [C++ MVP]" <rbv@xxxxxxxxxxxxx> wrote in message
news:ORV1HEgDJHA.528@xxxxxxxxxxxxxxxxxxxxxxx
Doron Holan [MSFT] wrote:
sermouse opens the underlying serial port just like an app does. are you
seeing this with the in box serial.sys driver? or with a
3rd party driver like one for a usb->serial device?
It's USB/serial converter, from FTDI (doesn't use communication
device class). Their driver is WHQL. I wouldn't doubt that their
driver is causing the problem since one version ago simply opening a
device on a multicore system was BSOD within 10 seconds. Which
doesn't totally absolve MS of responsibility. What's the good of
WHQL if even buggy drivers can be approved?
serenum and sermouse are out-of-the-box XP as far as I can determine.
I should be able to load the problem configuration in a kernel
debugger and have debug output from my userland application showing
the result of the device interface open. If someone could advise me
on how to enable tracing of serenum/sermouse or where to set a
breakpoint, I could determine the order of events definitively.
"Ben Voigt [C++ MVP]" <rbv@xxxxxxxxxxxxx> wrote in message
news:O7l7AheDJHA.2292@xxxxxxxxxxxxxxxxxxxxxxx
Doron Holan [MSFT] wrote:
for serial mouse detection, there is a window between detection
and driver load. serenum opens the port, detects the device,
closes the port and then enumerates the child device. the child
device stack will then attempt to open the port again. in
between the serenum close and the child stack open, your app can
easily open the port. if you do open the port in this window, the
serial mouse driver will fail to open the port and fail the pnp
start
What I observed was:
My application had an open handle to the port.
AND
The serial mouse driver was spamming my system with pointer motion
and mouse clicks.
I cannot tell you with certainty which opened the port first, I
just understand that it should not be possible for both sermouse
and a user-mode application to have the port open no matter which
goes first. My application opened the port using the device interface
path received through WM_DEVICECHANGE and SetupDi* queries. Is
there any chance that the way file sharing and exclusivity is
enforced might this and the DosDevices link these as separate?
Although, I should think that serenum and sermouse should also use
the raw interface path.
d
"Ben Voigt [C++ MVP]" <rbv@xxxxxxxxxxxxx> wrote in message
news:eGpGZ4VCJHA.2480@xxxxxxxxxxxxxxxxxxxxxxx
"Doron Holan [MSFT]" <doronh@xxxxxxxxxxxxxxxxxxxx> wrote in
message news:#erdV4SCJHA.2060@xxxxxxxxxxxxxxxxxxxxxxx
i agree with chris, i have never heard of this happening
I don't remember for sure, but I think I observed this behavior
fairly frequently when the device was surprise removed and
reinserted (i.e. bus reset) all before WM_DEVICECHANGE processing
for the original insertion completed.
Of course, it could be the communication protocol with the device
itself broke down and never reached the ready state. There's a
lot of additional testing needed on the system.
I am quite sure about the mouse issue though. I was able to
open a handle to the com port and Windows also decided to detect
a mouse. This shouldn't be possible, either Windows should
detect the mouse first and my CreateFile fails or else my
CreateFile succeeds first and then SERENUM can't listen for data
to run its heuristic mouse detection. There's another problem
where disabling the device in the WM_DEVICECHANGE handler
reliably and reproducibly shuts down the entire Windows Device
Manager / Plug and Play system. (This was one attempted
workaround for the aforementioned false mouse detection). This
is why I say WM_DEVICECHANGE isn't a 100% reliable method for
determining when the device is ready for use.
d
--
Please do not send e-mail directly to this alias. this alias is
for newsgroup purposes only.
This posting is provided "AS IS" with no warranties, and confers
no rights.
<chris.aseltine@xxxxxxxxx> wrote in message
news:1cc364ba-649e-4bae-b37b-925de49852a9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Aug 28, 8:13 am, "Ben Voigt [C++ MVP]" <r...@xxxxxxxxxxxxx>
wrote:
Next, WM_DEVICECHANGE is quite unreliable. It is necessary to
also poll the
list of ports (of course using SetupDi* functions, not
registry access, and
test the device state) because the user-mode WM_DEVICECHANGE
handler needs
an arbitrary amount of time to complete (by definition,
user-mode processes
can be blocked by higher-priority user or kernel tasks) and
some device insertion notifications are not delivered in this
case.
I've never heard of or observed this phenomenon, and your
explanation for why you think it happens is nebulous at best. Do
you have a reproducible example?
.
- Follow-Ups:
- Re: USB device detection via query registry information
- From: Doron Holan [MSFT]
- Re: USB device detection via query registry information
- References:
- Re: USB device detection via query registry information
- From: Doron Holan [MSFT]
- Re: USB device detection via query registry information
- From: Doron Holan [MSFT]
- Re: USB device detection via query registry information
- Prev by Date: Dynamic format change in AVStream mini-driver
- Next by Date: Re: What calls are made by taks manager to get list of processes?
- Previous by thread: Re: USB device detection via query registry information
- Next by thread: Re: USB device detection via query registry information
- Index(es):
Relevant Pages
|
