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Subject: Re: [PATCH v2] usb: serial: Repair FTDI FT232R bricked eeprom
To:     James Hilliard <james.hilliard1@gmail.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Johan Hovold <johan@kernel.org>,
        Lars Melin <larsm17@gmail.com>,
        Oliver Neukum <oneukum@suse.de>, linux-usb@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Russ Dill <Russ.Dill@gmail.com>
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From:   Hector Martin <hector@marcansoft.com>
Message-ID: <0bcb0208-04bc-40c8-7b42-56b4dcf93f21@marcansoft.com>
Date:   Fri, 11 Sep 2020 04:54:08 +0900
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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).

-- 
Hector Martin (hector@marcansoft.com)
Public Key: https://mrcn.st/pub