Re: [PATCH v2] usb: serial: Repair FTDI FT232R bricked eeprom

From: Greg Kroah-Hartman
Date: Fri Sep 11 2020 - 02:09:36 EST

On Fri, Sep 11, 2020 at 04:54:08AM +0900, Hector Martin wrote:
> On 11/09/2020 03.51, James Hilliard wrote:
> > I haven't tested this yet but my assumption was that either a kernel driver
> > or libusb can issue usb control messages, but both can not be bound to
> > a device at the same time. I figured this wouldn't have come up when you
> > tested your python script since the script likely predated adding the brick PID
> > to the ftdi_sio Linux kernel driver.
> Binding to interfaces is exclusive, but global device control messages are
> not issued to an interface. I think it should work even if the kernel driver
> is bound (this is how lsusb works too, since it issues control requests even
> to devices bound to drivers). Even if it is necessary to unbind it, though,
> libusb already provides a single function to do that
> (libusb_detach_kernel_driver).

You really should unbind the device from the driver when doing stuff
like this, so the kernel doesn't get confused.


greg k-h