Re: usb-autoload

[Okash Khawaja <okash.khawaja@gmail.com>]

Hi,

On Sat, Aug 26, 2017 at 03:48:40PM +0100, Okash Khawaja wrote:

> I am thinking of modifying speakup driver so that it can take in dev
> parameter after it has been loaded. Is there a simpler way?

Here's what I am thinking for usb autoload. Let's say speakup_usb_serial
is the driver which will be automatically loaded based upon usb vendor
and product id, when user plugs in native usb synth, such as triple
talk. speakup module will be pre-requisite for speakup_usb_serial so it
will already be in memory when following flow starts from inside
speakup_usb_serial. It assumes the native usb synth requires ltlk.
Functions of the form speakup.* are those exposed by speakup module.

First speakup_usb_serial will check if ltlk is already loaded
ltlk not loaded:
    1. speakup.next_load_as_delayed("ltlk"): tell speakup that very next
        time when ltlk is loaded, don't initialise it, i.e. don't call
        do_synth_init().
    2. load ltlk
    3. speakup.delayed_init("ltlk", "ttyUSBX"): tell speakup to first
        set dev_name of ltlk synth to ttyUSBX and then call do_synth_init

ltlk is already loaded:
    1. speakup.is_initialised("ltlk")?
    YES:
        > do nothing as ltlk is loaded and initialised so we assume it's
        being used
    NO:
        > speakup.delayed_init("ltlk", "ttyUSBX");

This should cover the scenario when ltlk is built into kernel.

Thanks,
Okash