Seeking Assistance: Implementing USB Device Suspend/Resume in User Space Driver

[Muni Sekhar]

On Mon, May 6, 2024 at 7:59 PM Alan Stern <stern at rowland.harvard.edu> wrote:
>
> On Mon, May 06, 2024 at 04:44:30PM +0530, Muni Sekhar wrote:
> > Dear Linux USB Subsystem Community,
> >
> > I hope this email finds you well. We are currently working on a USB
> > device driver in the Linux kernel space, which supports the
> > suspend/resume functionality for a USB device using the struct
> > usb_driver's .suspend and .resume callbacks.
> >
> >
> > In our driver code, we perform a check to determine if the device has
> > remote wakeup capability. If the device supports remote wakeup, we
> > enable the device's autosuspend mode by setting the struct
> > usb_device->dev.power.autosuspend_delay parameter and then calling
> > usb_enable_autosuspend().
> >
> >
> > Similarly, to resume the suspended device, we expose an API to user
> > space via IOCTL. In this process, we set struct
> > usb_device->dev.power.autosuspend_delay to -1 and then call
> > usb_disable_autosuspend().
> >
> >
> > While we have successfully converted most of the USB device driver
> > functionality from kernel space to user space using libusb, we are now
> > seeking guidance on how to implement USB device suspend/resume in user
> > space. Specifically, we would like to know if libusb provides support
> > for achieving the suspend/resume functionality mentioned above.
> > Additionally, any insights or suggestions on how to accomplish this
> > task would be greatly appreciated.
>
> Your question is about libusb, right?  So you'll get better answers if
> you post it on the libusb mailing list rather than the linux-usb mailing
> list.
Can USB device suspend\resume  be implemented in user space driver
using software other than libusb?
If so, what are those methods or techniques to achieve USB device
suspend\resume , can you please provide clarity on this.
>
> Alan Stern
>
> > It's worth mentioning that our USB device driver also supports
> > Bulk\Coontrol I/O transfers and other functionalities.
> >
> >
> > Thank you in advance for any assistance you can provide. I look
> > forward to your valuable inputs and recommendations.
> >
> >
> > --
> > Thanks,
> > Sekhar
> >



-- 
Thanks,
Sekhar