Re: [PATCH] usb: misc: supports Apple Carplay driver

[Chunfeng Yun]

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