Re: [PATCH] USB: ftdi_sio: Remove tty->low_latency.

[Johan Hovold]

On Tue, Sep 29, 2009 at 11:52:32PM +0100, Alan Cox wrote:
> > As it stands today ftdi_sio does indeed call tty_flip_buffer_push from
> > interrupt context with low_latency set and that is obviously incorrect,
> > right?
> 
> It seems to do it from a work queue - or did I miss a case ?

The function used for deferred work is actually called directly from
ftdi_read_bulk_callback: 

  ftdi_process_read(&priv->rx_work.work);

It only gets scheduled on the work queue when unthrottled (or if
tty_buffer_request_room(tty, length) < length before serial_throttle is
called).

So basically, unless throttled, it is always called from interrupt
context.

/Johan

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