Subject: Re: Console polling programming interface change (proposal)
To: =?X-UNKNOWN?Q?Jarom=EDr_Dolecek?= <email@example.com>
From: Bill Studenmund <firstname.lastname@example.org>
Date: 07/19/2001 10:48:37
On Thu, 19 Jul 2001, Jarom=EDr Dolecek wrote:
> to properly address quirks necessary for some weird hw, I'd like
> to be able to pass to/from cnpollc() a cookie value. It's necessary
> to change driver interface in order to support this.
> I propose these interface changes:
> * individual drivers' entry points would change to
> int (*cnpollc)(dev_t dev, int on, int cookie)
> i.e. handler would be function returning int, and taking one extra 'int=
> The handler is supposed to return cookie value for 'on' call (the 'cook=
> arg would be ingnored in that case), and accept cookie value as the 3rd=
> for 'off' call (return value would be always zero in this case)
> * current cnpollc() functionality would be split to two functions -
> =09 int cnpollc(void)
> =09 void cnunpollc(int cookie)=20
> cnpollc() would switch to polling mode and return cookie returned by
> driver, cnunpollc() would switch back to interrupt driven mode; the arg=
> is supposed to be the cookie previously returned by cnpollc().
> Opinions? I'd like to keep single driver console switch entry points
> for both 'on' and 'off'.
I gather right now it's 'void (*cnpollc)(dev_t dev, int on)' ? Another
void (*cnpollc)(dev_t dev, int on, int *cookie)
Then the caller doesn't have to do anything special about passing the
cookie in or out.