Re: [Linux-fbdev-devel] framebuffer_{alloc,release}

[James S. <jsi...@in...>]

> framebuffer_alloc doesn't assume anything. It allocates fb_info->par iff
> it's  told to. For  dual  head you  can allocate  par  yourself (and  do
> whatever you want with it) or do something like this (matrox fb is doing
> something similar):
> 
> if (seconday) {
>         fb_info = framebuffer_alloc(0, NULL);
>         fb_info->par = primary->par;
> } else
>         fb_info = framebuffer_alloc(sizeof(struct foo_par), NULL);
> 
> release_fb_info  won't  touch  fb_info->par  unless it  was  created  by
> framebuffer_alloc. If  secondary driver  can work  even when  primary is
> unloaded  then you  can  use  class_device_get (or  a  wrapper) to  keep
> primary fb data around:
> 
> if (secondary) {
>         if (!primary_fb_info)
>                 secondary_fb_info = framebuffer_alloc(sizeof(struct foo_par), NULL);
>         else {
>                 if (!class_device_get(&primary_fb_info->class_dev))
>                         /* primary is going away */
>                 else {
>                         secondary_fb_info = framebuffer_alloc(0, NULL);
>                         secondary_fb_info->par = primary_fb_info->par;
>                 }
>         }
> }

This is acceptable. I applied your changes.