Hi
On Thu, Feb 11, 2016 at 12:18 AM, Haixia Shi hshi@chromium.org wrote:
When USB cable is disconnected, we mark udl device as unplugged so that udl_detect reports connector status as disconnected, but still keep the drm device alive until user-space closes it.
Signed-off-by: Haixia Shi hshi@chromium.org Reviewed-by: Stéphane Marchesin marcheu@chromium.org
I assume this is based on the discussion I had with Stephane on IRC. I'm fine with going this way and keeping the device fully alive, and just treat the device removal as a connector-unplug. However, you really must document all this in your commit message.
Anyway, if you want to keep the device alive, then please change the code to entirely drop the "unplugged" flag and all related code. Then make sure you somehow reset "udl->udev" to NULL and make sure no code-path uses the usb-device after it was unplugged. I guess there should be appropriate locks already.
This way, you end up with a fully functional UDL device, which just happens to have to connector plugged. But you *really* have to be careful that no-one touches the usb device, as the interface might be re-used by some other device any time (or in case the usb-core provides protection against this, please document it).
Thanks David