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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Hector Martin <hector@marcansoft.com>
Cc: James Hilliard <james.hilliard1@gmail.com>,
	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>
Subject: Re: [PATCH v2] usb: serial: Repair FTDI FT232R bricked eeprom
Date: Fri, 11 Sep 2020 08:09:25 +0200	[thread overview]
Message-ID: <20200911060925.GA553486@kroah.com> (raw)
In-Reply-To: <0bcb0208-04bc-40c8-7b42-56b4dcf93f21@marcansoft.com>

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.

thanks,

greg k-h

  reply	other threads:[~2020-09-11  6:09 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-09 19:34 [PATCH v2] usb: serial: Repair FTDI FT232R bricked eeprom James Hilliard
2020-09-10  3:02 ` Oliver Neukum
2020-09-10  3:17   ` Hector Martin "marcan"
2020-09-10  3:46     ` James Hilliard
2020-09-10  3:49       ` Hector Martin "marcan"
2020-09-10  4:39         ` James Hilliard
2020-09-10  3:40   ` James Hilliard
2020-09-10  3:46     ` Hector Martin "marcan"
2020-09-10  4:07       ` James Hilliard
2020-09-10  5:33   ` Lars Melin
2020-09-10  6:48     ` James Hilliard
2020-09-10  8:01       ` James Hilliard
2020-09-10  8:08     ` Johan Hovold
2020-09-10  8:17       ` James Hilliard
2020-09-10  8:55         ` Greg Kroah-Hartman
2020-09-10  9:52           ` James Hilliard
2020-09-10  9:57             ` Hector Martin
2020-09-10 18:51               ` James Hilliard
2020-09-10 19:54                 ` Hector Martin
2020-09-11  6:09                   ` Greg Kroah-Hartman [this message]
2020-09-10  5:49 ` Greg Kroah-Hartman
2020-09-10  6:45   ` James Hilliard
2020-09-10  8:10     ` Hector Martin

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