Re: ioctl number 0xF3

[Thomas Winischhofer <thomas@winischhofer.net>]

Francois Romieu wrote:
 >He can surely tell when an egg stinks. However Arjan is not a chicken.

I didn't mean that as any sort of insult. I am just tired of the XFree86 
people telling me "implement a generic interface". I write one single 
driver and want the users of this driver to have some sort of comfort. 
Waiting until someone comes up with some generic solution (for a design 
of which I don't have time nor the required knowledge about a zillion 
different systems) I am old and grey.


> Thomas Winischhofer <thomas@winischhofer.net> :
>>Is 64 out of, what's that, 65536 too much to ask? Well, I could live 
>>with 32 as well...
>
> Reserving a generous ioctl range without any clear interface will make
> some people nervous. If you can not specify the interface now, try to
> separate the generic/specific part of it and use sub-ioctl for the really
> scary things as it will make the future life easier.
> 
> If you have some pointers to the existing code, that may help too.

Well, before I start implementing it (further), I thought it would be 
smart to be able to rely on certain things. As long as I don't even know 
if I get the numbers I don't write code... but frankly, the current 
development sisfb version available on my website has a very few of the 
intended ioctls already implemented.

The interface I intend to use matches the one the X driver has (using 
the Xv extension as an ioctl replacement) and will be documented. Since 
I develope both the SiS kernel framebuffer driver as well as the SiS X 
driver this will reduce duplicate code and ensures good cooperation. 
Furthermore, there could be a common library for both the framebuffer and X.

Hm. Were the matrox folks asked for a "clear interface" in advance when 
they started using the 'n' ioctls? Am I too polite? ;)

sisfb uses a few ioctls already, as an extension to the generic fb 
related ioctls. (Although the version currently in mainline 2.4 is not 
in any way 32/64 bit safe, and neiter is the mainline 2.6 version yet as 
regards the obviously required ioctl32 emulation stuff - investigating 
this at the moment).

Thomas

-- 
Thomas Winischhofer
Vienna/Austria
thomas AT winischhofer DOT net          http://www.winischhofer.net/
twini AT xfree86 DOT org