[quoted lines by Luke-Jr on 2014/02/23 at 19:03 +0000]

>I was looking at the circumstances surrounding ftdi_sio, which uses the 
>generic implementation.
>
>wouldn't it be possible to just ask less often to 
>reduce the bandwidth load?

That's sort of what we do in brltty's user-space implementation for serial 
adapters which use bulk input endpoints. And, yes, the ftdi_sio chip is a 
problem since it always has pending data (even if it's just status bits). What 
we do is back off by increasing the delay by powers of 2 up to a maximum as 
long as we're only getting status bytes, but go back to immediate as soon as we 
get data. We also only use a single URB. It works quite well.

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