Re: USB Gadget Filesystem HID stuck on write when using mass storage at the same time
From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-06-29 17:20:56
On Tue, Jun 29, 2021 at 03:45:46PM +0200, Benjamin Marty wrote:
Hello In my application, I boot a Linux System through USB Gadget mass storage and at the same time pass in USB Touch commands via USB HID Device. Both over the same USB OTG Gadget Link. If I execute USB HID commands during high traffic over the USB Mass Storage, the HID device gets stuck. Writes to it are then blocking forever. I'm not sure if I use something wrong or if this is a Kernel issue. Do I maybe need to check something before I'm allowed to write to the HID device? Hardware issue are unlikely, I tried it on the Raspberry Pi Platform and also on the NXP iMX8MM platform. Both have this HID device stuck issue. I have also tried multiple Intel Computers as USB Host. I tried to document my issue here with test scripts to replicate what I do in my C Application with the same result: https://github.com/raspberrypi/linux/issues/4373
What kernel version are you using for your device? What is locking up, the kernel on the device, or the kernel on the USB host side? And have you used usbmon to look at the USB traffic to ensure that you really are sending the data you think you are sending? thanks, greg k-h