Windows: libusb Windows hotplug support

[mcuee]

This is one of the long standing missing feature for Windows.

[mcuee]

Last known tree back in the libusbx time.
https://github.com/dickens/libusbx-hp/tree/windows-hotplug-3

[changyp6]

libusb hotplug for Windows is really important.
I have a program running on Linux/Window/MacOS, but Windows doesn't have hotplug support, I have to write my own device detection code for Windows.
But Windows only reports that there is a device arrived or there's a device removed, you have to find which one is added or removed.
So when I receive device remove event, I usb libusb_get_device_list() to get current device present in the system, and compare this list with the old one to find out which one is removed, and I use the same method to find which one is added, after I find the difference, my program will handle the removed/added device.

But if I unplug the device and plug it back to the same USB port very quickly, and Windows's driver searching program is disabled(to make system recognize device faster), my program can get device remove and device add event correctly, but libusb_get_device_list() will get a usb device list the same as the previous saved one.

Here is the reason:
When my program receives device remove event, and start to list all the USB devices, because the unplug/plug action is so fast, libusb_get_device_list() will give a list after the device is plugged back. So this USB device list is the same as the list before unplug/plug action, which means my program cannot find out which device is removed and which is added, there will be 2 missing actions for my program.

Because my program is event driven, this causes 2 events missing.

I really hope that hotplug feature can be implemented for Windows.

[mcuee]

https://github.com/dickens/libusbx-hp/tree/windows-hotplug-3 You may want to try the above old branch to see the hotplug code there works for your application. I am not so sure how much efforts need to bring that branch up to date though.

[changyp6]

I tried that before, I even tried to merge the change into libusb 1.0.19, but I failed to merge it to newer code. I still need to use latest branch, because there are tons of bug/leak fixes for Windows platform.

Hope Windows hotplug support can be implemented soon.

[dickens]

Will be part of the next release. Unfortunately it is a complicated set of
changes.

Regards,
Chris

[changyp6]

This is a great news!

[chrisba77]

were there any changes regarding the hotplug issue since then? Currently having the problem with LibUsbDotNet that communication with an unplugged-replugged device is only possible again after reinstalling the driver using the Inf-Wizard OR restarting Windows. This device is a CardReader. On the other hand, i dont have issues hotplugging a USB Keyboard. Does anyone have suggestions?

[diabolo38]

@chrisba77 strange w/o any "hotplug" support you should be able to re-use the device without driver re-install reboot etc
if:
-release any claimed interface
-close the device
-call exit on the libsusb context

then run again lib usb init , device detect ,re-open re claim etc ..

That is what i do to get control again of unplugged and re-pluged device
not real nice but the simplest i did find.

[chrisba77]

@diabolo38 I do all this. And actually after plugging in the device again, communication is possible. BUT the read values coming from the device are not valid anymore.
After reading in a Tag / Card the device sends some HID reports with Number-Keys including a Return Hit. After unplug / replug, these values seem to be random. Checked with Port Sniffer that I read the right values coming from the device. But sent Key Hits are not valid anymore and change every time i read in the same Tag. Reconnecting or Restarting my Test-SW doesnt help. Only thing that helps is rerunning Inf-Wizard or a reboot.

[diabolo38]

@chrisba77 if device is hid using standard os hid device driver then the issue could be os driver or the device itlsef. I can't see such issue with non hid device at least.

[tony--]

It looks like this didn't make it into 1.0.21 as planned.
Any plans to include this in 1.0.22?
Thanks in advance!

Edit: I see now that it is included in the 1.0.22 milestone. I'll also take a look at the mailing list archives to see if there is recent discussion. Any additional info would still be welcome!

[Jam-Nibi]

Hi guys, what's the status of this issue ?

[leileigong]

Did the hotplug supported on windows?

[jazzy-crane]

Has this now been moved to 1.0.23? :(

[changyp6]

I just checked the latest code, it seems that windows hotplug hasn't been implemented.
Windows libusb hotplug definitely is my first 2018 new year wish.

[njk42]

+1 for Windows hotplug support.

Without hotplug support, what are the standard ways of determining when a device connects or disconnects on Windows? Does one just repeatedly poll a device list and determine when there are changes detected?

[ryxuli]

It's really inconvenient that libusb doesn't support hotplug capability on Windows. I finely turn to libusbK. It can be downloaded from https://sourceforge.net/projects/libusbk/, after setting up, you can download the whole src zip in https://sourceforge.net/projects/libusbk/files/libusbK-release/3.0.7.0/libusbK-3.0.7.0-src.zip/download which includes an example hot-plug-monitor.c shows the hotplug ability.

[rjgc2015]

Hi all, did it support on Windows now？

[mcuee]

Unfortunately not. Right now only Chris is working on the Windows side and it will take some time to get this. -- Xiaofan

[cor3ntin]

Is there any update on that? Thanks a lot

[Timmmm]

Is anybody working on this?

[changyp6]

Now, this Hotplug has become my 2019 new year wish.

[wanpp]

Now, this Hotplug has become my 2019 new year wish.