From: Chunfeng Yun <chunfeng.yun@mediatek.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Serge Semin <fancer.lancer@gmail.com>,
Guenter Roeck <linux@roeck-us.net>,
Kate Stewart <kstewart@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Alan Stern" <stern@rowland.harvard.edu>,
<linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH] usb: misc: supports Apple Carplay driver
Date: Wed, 14 Mar 2018 16:20:52 +0800 [thread overview]
Message-ID: <1521015652.3717.28.camel@mhfsdcap03> (raw)
In-Reply-To: <20180314061612.GA17263@kroah.com>
On Wed, 2018-03-14 at 07:16 +0100, Greg Kroah-Hartman wrote:
> On Wed, Mar 14, 2018 at 02:02:36PM +0800, Chunfeng Yun wrote:
> > The driver is used to support Apple carplay feature by a debugfs
> > interface which can force the driver to send a USB Vendor Request
> > of "Apple Device to Host Mode Switch" to switch Apple Device
> > into host mode.
>
> While I am all for crazy debugfs interfaces, I would _strongly_ suggest
> not doing that here for the main API to the device. I know Android is
> trying to prevent any new devices from even enabling debugfs, and as the
> file system requires root permissions by default, you are forcing any
> user of your new api to run as root, which is not a good idea either.
>
> Given that all you are doing here is a single usb control message, why
> does this even need to be a kernel driver at all? Can't you do the same
> thing from userspace with a simple libusb/usbfs program? Or even a
> simple script?
Ok, I'll abandon this patch, and do it by libusb
Thanks a lot
>
> thanks,
>
> greg k-h
next prev parent reply other threads:[~2018-03-14 8:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-14 6:02 [PATCH] Add Apple Carplay driver Chunfeng Yun
2018-03-14 6:02 ` [PATCH] usb: misc: supports " Chunfeng Yun
2018-03-14 6:16 ` Greg Kroah-Hartman
2018-03-14 8:20 ` Chunfeng Yun [this message]
2018-03-14 6:53 ` [PATCH] Add " Matthew Dharm
2018-03-14 8:18 ` Chunfeng Yun
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