Re: [PATCH] Re: Reboot resistant USB bug

[Emmanuel Dreyfus <manu%netbsd.org@localhost>]

On Thu, Oct 25, 2018 at 07:59:36AM +0000, Emmanuel Dreyfus wrote:
> 3) Use USB timeout in usbd_transfer()
> https://ftp.espci.fr/shadow/manu/usb_sync_xfer.patch
> 
> Make sure the USB timeout is used when doing synchronous USB transfers.
> Here again the goal is to avoid getting stuck in the kernel forever
> because the ack frame was rejected by the host controler.

After investigating, that one is not necessary. I thought I got stuck
forever in cv_wait but in fact I was entering it again and again because
processes were pushing new requests.

On the otherhand, I made some progress with enabling libnfc to handle
the toggle bit problem. It detects a read timeout as a toggle bit miss, 
and sends an empty frame to resync it. But in order to proceed, that
hack must not fail its write operation. I let it go despite a toggle
miss related write timeout by adding a quirk that hides the timeout.

https:///ftp.espci.fr/shadow/manu/toggle.patch

That is horrible, but the hardware is really buggy, despite being
widespread.

-- 
Emmanuel Dreyfus
manu%netbsd.org@localhost