On Sun, 21 May 2006, Johannes Stezenbach wrote:
> It cannot be called from dvb_unregister_frontend(), as the whole
> point of this exercise is that dvb_attach/detach is optional.
>
> So, it must be called by the card drivers, right after
> the dvb_unregister_frontend() call, and it should simply do:
>
> #define dvb_detach(function) symbol_put_addr(function)
>
> (As a minor complication, fe->ops.release needs to be
> saved in a temporary between dvb_unregister_frontend()
> and dvb_detach().)
Two other options:
Add a parameter to dvb_unregister_frontend(fe, int dynamic), that
enables the detach code.
Create a new function, dvb_unregister_frontend_dynamic(), that
does the same thing.
This would allow for less duplicated work in the card drivers, and
dynamic attachment would still be optional and controlled by the
driver.
> We should also add a BUG_ON(!fe->ops.release) to
> dvb_register_frontend(), and remove the bogus
> warning printk from dvb_unregister_frontend().
Unrelated to dvb_attach(), but some of the radio drivers don't have
release() methods.
> Or, maybe we should handle this via Kconfig? So
> that you can add the dvb_detach() to dvb_unregister_frontend(),
> but one can disable dvb_detach/dvb_detach via
> CONFIG_DVB_FRONTEND_STATIC_DEPS?
This would be a nice ability. Necessary really, if you want to use
symbol_out_addr() and support pre 2.6.17 kernels. I think what ever is
done should support:
1. Continue to work with pre 2.6.17 kernels, without dynamic attachment
compatibility if that is too hard.
2. Be possible to turn off with Kconfig. If 1 is supported, this should be
trivial.
3. Not be forced on all drivers. A driver that supports a dozen front-ends
can use dynamic attachment, a driver that supports a single front-end
can continue to use static attachment.
4. Continue to work with non-module supporting kernels. The symbol_xxx()
macros more or less turn into no-op code when modules are turned off.
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