Re: [rfc][patch] DRM initial function table support.

[Ian Romanick <idr@us.ibm.com>]

Dave Jones wrote:
> On Tue, Aug 31, 2004 at 02:11:11PM +0100, Dave Airlie wrote:
> 
> One thing that would make things even nicer would be..
> 
> instead of this..
> 
>  > +void gamma_driver_register_fns(drm_device_t *dev)
>  > +{
>  > +	dev->fn_tbl.preinit = gamma_driver_preinit;
>  > +	dev->fn_tbl.pretakedown = gamma_driver_pretakedown;
>  > +	dev->fn_tbl.dma_ready = gamma_driver_dma_ready;
>  > +	dev->fn_tbl.dma_quiescent = gamma_driver_dma_quiescent;
>  > +	dev->fn_tbl.dma_flush_block_and_flush = gamma_flush_block_and_flush;
>  > +	dev->fn_tbl.dma_flush_unblock = gamma_flush_unblock;
>  > +}
> 
> having a per-driver struct with regular C99 initialisers..
> 
> struct gamma_driver_fntbl {
> 	.preinit = gamma_driver_preinit,
> 	.pretakedown = gamma_driver_pretakedown,
> 	.dma_ready = gamma_driver_dma_ready,
> 	.dma_quiescent = gamma_driver_dma_quiescent,
> 	.dma_flush_block_and_flush = gamma_flush_block_and_flush,
> 	.dma_flush_unblock = gamma_flush_unblock,
> };

I think the intention is to have default functions set in the 
device-independent code and have the device-dependent code over-ride 
them.  Since the defaults may not always be NULL, doing a struct like 
that wouldn't really work.  I suppose we could have a struct and a 
device-independent function that copies the non-NULL pointers from the 
per-device struct.  Would that be better?

> Thanks for doing this work, it really is starting to look a little more
> like a Linux driver 8-)

I second that!