Do you know a way to use the Windows XP API to reset the USB bus? In other words, I'd like the OS to kick out any USB devices that are currently connected, and then auto-detect everything anew.
I'm aware of devcon, and I suppose I could do system calls out to it, but I'm hoping for a direct call into the API.
From kernel mode: You can force a specific USB device to be re-connected, as if it was unplugged and replugged again, by sending an IOCTL_INTERNAL_USB_CYCLE_PORT to its PDO. (This can only be done from a kernel mode, e.g. through a helper driver.) This 'cycle' operation will cause a USB reset to occur, after which the device would be re-enumerated. For example, if the device comes back with a different USB device descriptor, a different driver may be matched for it.
From user mode: You can do this by ejecting the device through the CfgMgr API. For example, to go over all USB hubs and eject all devices:
Find all devices having device interface GUID_DEVINTERFACE_USB_HUB with SetupDiGetClassDevs(... DIGCF_DEVICEINTERFACE).
Enumerate over the returned device information set (SetupDiEnumDeviceInfo).
For each device, get the DevInst member:
Invoke CM_Get_Child(DevInst) and then CM_Get_Sibling repeatedly to go over all child nodes of the hub (i.e. the USB devices).
For each child node, call CM_Request_Device_Eject.
Well, use can use the Setup API (SetupDiXXX functions) to enumerate the USB devices in the system, and then call WinUsb_ResetPipe on each one, but I'm not sure if that's what you're looking for. It's been a while since I worked with USB devices, but as I recall, there is no standard way to reset a device (i.e. simulate a power off/power on cycle). If it's possible for a particular device, you'd have to send an appropriate IOCTL (using DeviceIOControl) to the driver. The IOCTL would vary from manufacturer to manufacturer.
It's possible to cycle the parent port on the USB hub the device is attached to, as well. This will result in, among other things, apparrent unplug/replug actions, as you will see a balloon popup when this occurs.
Much of this is poorly documented, and honestly, I've gotten the impression there are only a handful of people at Microsoft who really understand it well. The design decision I've made for future devices I design is that I intend to include watchdog functionality on both sides, as well as a device-side full reset function. That way, if the device figures out it is confused, it can just cut its own power for a second and fully reset, if the host can't communicate with it, it could do the same thing, and if the device thinks everything is fine but the host knows better, the host could order it to reset.
There are at least three APIs worth looking into for this problem: the Setup API, the Config Manager API, and various WMI extensions. However, be cautious about diving into WMI if you intend to use an Embedded XP target, as you will have to include a lot of other things in your OS image you might otherwise not need.
As far as I know, there is no way to do this - you can issue a command to have PnP rescan the bus for new devices, but that isn't the same as issuing a bus reset.
Furthermore, just because from a hardware perspective you issued a bus reset doesn't mean that Windows will remove the PDOs that represent the children of the hub and redetect them; the USB bus driver can (and does) do just what I describe (i.e. issue hardware bus resets without disturbing the device tree), and only after the device doesn't respond does it issue the surprise removal and yank it from the tree.
Related
I have an usb device (pole display), which i don't have driver for.
I installed generic usb driver and opened the port for sending(I use bulk transfer) data to device.
With usb monitoring software i see my data gets to device, but nothing much happens on device side.
The device commands(ESC/POS) work when transfered over (virtual) com port, but not over usb port.
Shouldn't device process commands the same way regardless connection type (com vs usb)?
How can i figure out what commands work with the device (for example, if i send some text, i want it to show on display)?
Any help is appreciated!
Look at the USB descriptors the device reports in order to determine its class. If it is a custom device and not a standard class then you'll likely not be able to work with it. There is a big difference between old RS-232 COM protocol and USB. USB devices can have multiple configurations and endpoints, each responding to data in different ways. Many classes exist and are pretty standard (CDC-ACM is typically used for virtual serial ports.) However, it's not uncommon for device manufacturers to include OEM specific configurations and endpoints which can be used for their own custom interfaces, firmware loading, etc.
Is there any initialization data transmitted through the COM port when connecting the device? The device surely can treat COM and USB different, but another possible thing that goes wrong is that the device needs to hear some sort of "I'm going to start sending commands"-signal from you first, and that signal may be different between COM and USB.
So what I would recommend is first (if you have not done that yet) see what data is sent to initialize the COM connection, and if that doesn't have an obvious USB counterpart, connect it to a PC where you do have drivers (assuming that is available somewhere and somehow, which is possible if e.g. you ask this due to OS incompatibility) and see how the connection is initialized there.
If the first doesn't work and the second is unavailable to you, then I'm afraid there's little I can do to help you, since it's usually not visible for you what commands the device wants to hear other than by guesswork, documentation, or comparing to similar devices where you do have that data available.
I am wondering whether it is possible to display a message to the user when he connects a USB device. For example, I want to program the USB so that any PC that the device is connected to displays the pop-up window, saying Please leave the usb on this place.
It is NOT possible;
You wrote: " I want to program the usb so that any PC that the device is connected "
You'd rather program the PC not the USB
USB is a storage device only. Unfortunatelly you can't program all the PC's that USb might get into
The ONLY way this might be (yes it won't work in every case I guarantee) be tweaked is to have autorun.inf file in the USB pointing to a program on the USB that displays the message you want.
[Autorun]
Open=msg.exe
Due to most modern operating systems have tons of blocking mechanism to stop autorun programs this message has very slight chance to appear
You will need to first register for device notification. Then, you can implement a callback to detect when your USB device is inserted or removed. Within that callback you can do your messaging to the users based of your inspection of which device was inserted or removed.
This is only possible if the computer already has a driver installed for this device that implements this behavior. If, as I suspect, the device is actually a standard USB storage device, this is not possible.
I need to set up USB communication between a Windows 7 host and a Linux device for data transfer. I was able to compile the Linux kernel on the device to include the Gadget Zero driver in the kernel (not as a loadable module - Linux version 3.0.15). My project has some requirements, which also explains why I chose Gadget Zero:
1) On the Windows 7 host, a kernel mode driver must be used to communicate over the USB connection for sending and receiving bulk data. (speed is not important, not a lot of data at once).
2) On the linux device, no requirements on USB side except send and receive data easily over USB link. The data received will eventually be "unmarshalled" to call functions in another kernel module (and those responses packaged and sent back to the host).
3) Multiple linux devices will be connected to the host, so need easy way to enumerate connected devices and communicate with them.
So due to the requirements, I decided against the Gadget Serial. I'm having serious issues sending and receiving data over the virtual COM port in kernel mode (KMDF) in Win 7 host. WinUSB does not seem to want to open my attached device (I'm using KMDF windows USB driver from template in VS2012) Also, the gadget serial driver on the linux side, I cannot find the functions where the data is received and sent. Plus, any received data on the linux device seems to be echoed back to the host for some reason. (and to test this, I wrote a simple user-mode app in Windows, which is a no-no for my project).
Gadget Zero, it appears much simpler on the linux side. I can plug the USB cable to the Win7 host, and I can get the device to appear in the device manager. However, again I am having problems with getting communication going over the link. Gadget Zero has 2 bulk endpoints, so this shouldn't be an issue. Surely, someone has made data communication possible between a Windows host and a linux device using Gadget Zero? With Gadget Zero, it should be easy to enumerate the connected linux devices and communicate with them.
The trick is to keep the Windows side communication in kernel mode. Can someone point me in the right direction perhaps with Gadget Zero, Windows 7 KMDF, and some sample source code? I have a hard time believing no one has done this before because my internet searches don't turn up much. (and mostly user-mode solutions with Gadget Serial).
Thanks!
So you're writing a Win32 driver in which you want to communicate with your linuxed usb? I haven't written much win32 kernel code, but I believe I've seen a huge section in the doc, saying something like "This is how you make usb drivers"... That'd be it. In other words, when in kernel mode you have access to the full kernel usb layer. You don't need an existing driver or whatnot.
On the linux side you can use the serial gadget, in a different run mode. Only the default run mode, registers it self as VCP. There exist a more basic mode:
modprobe g_serial use_acm=0
Give it your own vendor id and you'll be able to attach your very own custom win32 driver. The 'multiple linux devices' will be handled by Windows. (Multiple instances of your driver, will be initiated.)
The echo you're seeing btw, is most likely a terminal feature. (The terminal mode on uarts will echo.) You have to disable it, when connecting. And now that you're at it, you also have to disable the xon/xoff, esc chars etc. (Standard legacy rubbish.)
And another thing. I'm not sure the gadget zero actually sends the data onto the line. It's meant for testing the gadget framework. (I could be mistaken though.)
Anyway, you've prolly solved this issue years ago. I'd be nice to know what you came up with.
I wonder if anyone can help at all, a bit of a specialist problem this.
I have an application that needs to read and analyse a number of USB devices (not simultaneously, they are each run in seperate tests and could in theory be run on different machines).
Each of the USB devices is based on the USB HID class, and are manufactured by different companies, none of these USB devices are designed to be run on PC, but are meant for a different platform, however for the purposes of testing the devices the client has requested that the test application is run from a PC.
Some of the devices will start up, be recognised by windows which will initialise and start them correctly using the generic HID class driver built into windows, the devices will then start sending correct data packets of the data to be tested.
Some of the devices will start up, be recognised by windows which will try to start them but fail to fully to initialise them leaving them in a half initialised state. This is fine, as I can use my beagle protocol analyser to capture the initialisation packets from the genuine platform and then use the LibUSBDotNet library to replicate the remaining packets in the initialisation sequence and get them to start sending the packets correctly.
The problem I have is with one particular device (though there are some more I haven't tested yet so it's quite possible one of those may also exhibit the same problem). The issue is the the Windows HID class driver recognises the device and trys to initialise and start it, this works after a fashion and the device starts sending data.
The problem is that the data being sent is different to that which is sent to the genuine platform (containing only a subset of the full data). It's as though windows has initialised the device into a different mode.
When I capture the initialisation packets from both the PC and the genuine platform using my USB protocol analyser I see that Windows is sending some slightly different initialisation packets. Using LibUSBDotNet to resend the correct packets once Windows has already started the device seems to have no effect.
My problem is that I need to stop windows from trying to initialise the device using the standard HID class driver, I've tried removing the driver in Device Manager but it still initialises it (and the driver is magically reassigned in device manager). I've done some investigation and there are possible alternatives:
Create a specific driver which windows will assign to the particular VID/PID of the device but that does nothing, then I can use LibUSBDotNet to send the correct initialisation sequence to the device from within my own code.
Use something like WinUSB to create a proper driver for the device (or possibly to create a "dead" driver like 1.
Will a driver with a specific VID/PID defined be used by windows in preference to it's inbuilt USB HID class driver? If not then I would be wasting my time going down this route?
Note, my mac initialises the problem device correctly, and I've asked the question of the client whether the application can be developed for Mac and their answer was frustrating Windows only.
I've no experience in writing proper Windows drivers, though I have experience in talking to USB at a relatively low level (so that part doesn't worry too much). Can anyone suggest a good course of action (before I potentially waste weeks investigating how to write drivers for the PC only to find my selected course of action can't deliver what I required).
Any help or suggest much appreciated.
Thanks,
Rich
Added after trying suggestions below:
I tried using the LibUsbDotNet inf wizard to create the necessary files and install them and this appeared to work - certainly the device was now appearing in Device Manager as a libusb-win32 device - not HID device and the associated driver was libusb driver. Even after doing this the device still seems to become initialised and start sending the wrong type of data packets although now those packets are no longer handled by the class driver and are just lost.
I also came across Zadig which has a similar inf creation wizard for WinUSB and this had exactly the same result.
A colleague has suggested that it might not be windows itself that is switching the device into this mode, rather the device identifying that it is connected to a windows machine and switching itself into this mode. I suspect this is the case, in which case I am stuck - time to have another conversation with the client.
Many thanks for the help.
You're using libusb-win32 as a filter driver; that is, the HidUsb device driver is assigned and loaded for your device, but then the libusb-win32 driver is loaded on top and gives you unobstructed access to the hardware.
If you don't want a HidUsb (or any other class driver) to perform any communication "on your behalf", simply associate libusb-win32 as a device driver with your hardware. For this, you'd have to create an .INF file associating it with the VID/PID/Revision of each USB device. If I recall correctly, libusb-win32 even comes with a utility to generate such .INF files.
If you install this .INF file e.g. with PnpUtil.exe (available on Vista or higher), you might still run into issues where, although you're a better match than the generic HID driver, the HID driver is still selected.
The generic HID driver matches devices by their Compatible IDs (i.e. by a USB interface class) while you'd be matching by Hardware IDs (which have higher priority). However, Windows might give priority to other aspects, such as your driver being unsigned. Read: How Windows Selects Drivers
Luckily, even in that scenario, signing drivers with a self-generated certificate (use CertUtil.exe, MakeCat.exe and SignTool.exe) is not too difficult.
I'm looking for a very specific USB device for debugging systems that may use USB but not with a regular computer (proprietary hardware). I want a device that has a USB host controller and two USB device connections. The device to be debugged is connected to the USB host controller and one of the device connections is connected to another device with it's own host controller on it. The the other device connection is connected to a pc. The point being that all USB data travelling through the device (from the device connected to the host controller to the device connected to the first device connection) is reported to the pc.
I'll happily write software to do the logging (in fact I want to) but I can't seem to find a board like this anywhere. Can anyone help?
I have an Ellisys USB analyser, which isn't exactly what you describe internally, but does sit between a peripheral and a host and use a separate PC to collect the data.
(i.e. it has two 'B' and one 'A' connectors on it.)
Excellent product, and very helpful company.
Sniffing the USB shouldn't be too hard if you have the right hardware. And that is the tricky question. I haven't seen anything that describes the USB breakout box that you want. However I can say that this is in the realm of the following two magazines:
Nuts and Volts
Circuit Cellar
If they don't have a USB breakout box project in their archives, then at least they will have advertisements for small cheap single board computers that would have multiple USB ports that you can use for buffering the signals and reporting it back to your PC.
Alternatively is it possible to just wire your PC up to the middle of your two devices and write a custom drive that echos data back and forth while sniffing off a stream for you?
Sorry for the long delay in my reply -- I checked out one of our USB developer's toolchain, and he uses a Beagle USB Sniffer. He seems happy with it.
You're looking for a USB device with two upstream outputs. I think according to the USB spec, this is not possible. You will have two USB hosts trying to send messages and control the USB devices at the same time.
What if you were to look for a device which allowed you to view the data going through a hub via something other than a usb output?
If you're building something custom, take a look at this USB chip site. The chips are programmable via a windows application. Once you define how you want it to operate, it's saved on an EPROM on the dev board ($30-$50).
Sorry if this isn't helpful!