[PATCH 2/3] drm: fb_helper: implement ioctl FBIO_WAITFORVSYNC

[Stefan Christ]

Hi Daniel,

I finally found some time to look into this issue again.

On Fri, Jul 15, 2016 at 09:19:22AM +0200, Daniel Vetter wrote:
> <snippet>
> 
> To roll new vfuncs out consistently I think it'd be great to create a
> DRM_FB_HELPER_DEFAULT_OPS #define which sets all the fb_ops. Drivers can
> then overwrite just what they need, e.g.
> 
> static struct fb_ops drm_fbdev_cma_ops = {
>       .owner          = THIS_MODULE,
>       DRM_FB_HELPER_DEFAULT_OPS,
>       .fb_mmap        = drm_fb_cma_mmap,
> };
> 
> Maybe even include the .owner = THIS_MODULE line in the macro, but that
> might be too much magic and mislead people into reusing it when it's not
> the same module.
> 
> Of course this would be an additional (subsystem-wide) prep patch before
> this one here.
> -Daniel

Ok. This pattern seems like single inheritance in object-oriented programming
languages ;-) The define looks very reasonable since these drm helper functions
are used in lot of drivers.

I would also not include '.owner = THIS_MODULE' in the define, because it would
contain even more magic.

What is the preferred way for subsystem-wide patches? One big patch, one patch
per driver or group of drivers per patch?

Mit freundlichen Grüßen / Kind regards,
        Stefan Christ

> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch