Re: RFC: btusb firmware load help

[Marcel Holtmann <holtmann@linux.intel.com>]

Hi Matthew,

> > Right -- so ath3k depends on some atheros USB device IDs, and its a
> > stupid driver that just loads firmware. The problem with this new
> > device is that it requires two phases. One to load some sort of
> > firmware onto it to get it to read as an ath3k device, and then ath3k
> > will load the right firmware to it. So the hardware device is already
> > claiming a btusb vendor:device ID, we can't change that I believe. Of
> > course for future devices we can, and we've addressed this and its
> > been fixed.
> 
> If the device IDs can be changed when the firmware is loaded, then 
> simply provide a driver that binds to the original IDs and uploads the 
> firmware. The original IDs can be blacklisted from btusb so it won't 
> interfere. The device will then boot the firmware, detach and reattach 
> with new IDs - btusb will then bind. Repeat for every cold reset.
> 
> If you can't change the IDs from firmware then an alternative would be 
> to blacklist it from btusb and provide a userspace application triggered 
> by a udev rule. Have it load the firmware and then poke 
> /sys/bus/usb/drivers/btusb/new_id .

exactly, we just blacklist the original USB IDs in the btusb driver. It
already has a blacklist table and you just use BTUSB_IGNORE in there.

Regards

Marcel