[PATCH] drm: Document mode_config.max_width/height as the max fb dimensions

[Manasi Navare]

On Fri, Jun 15, 2018 at 08:39:39PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The meaning of the mode_config max_width/height fields has not been
> entirely clear. They are used both as the max framebuffer dimensions,
> and they are also used by drm_mode_getconnector() to filter out
> any mode whose hdisplay/vdisplay exceed those limits.
> 
> Let's put it in writing that max_width/height only refrer to the max
> framebuffer dimensions, and should those be higher than the hardware
> limits for display timings the driver must validate the latter using
> some other means.
> 
> We'll keep the max_width/height usage in drm_mode_getconnector()
> because setcrtc treats hdisplay/vdisplay also as the primary plane
> width, and having a plane bigger than the max fb size doesn't make
> much sense (if we ignore scaling that is). It all works out fine
> as long as the max fb dimensions are at least equal to the max
> timing limits. If the opposite were true we may want to rethink
> what drm_mode_getconnector() does. Maybe do the mode filtering
> only for non-atomic userspace?
>

Yes this makes sense and as we support higher resolutions, we need to update
the fb_width and fb_height maximum values so those modes dont get
filtered out.

This looks good to me.

Reviewed-by: Manasi Navare <manasi.d.navare at intel.com>

Manasi
 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  include/drm/drm_mode_config.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> index fb45839179dd..f796691b2d09 100644
> --- a/include/drm/drm_mode_config.h
> +++ b/include/drm/drm_mode_config.h
> @@ -329,10 +329,10 @@ struct drm_mode_config_funcs {
>  
>  /**
>   * struct drm_mode_config - Mode configuration control structure
> - * @min_width: minimum pixel width on this device
> - * @min_height: minimum pixel height on this device
> - * @max_width: maximum pixel width on this device
> - * @max_height: maximum pixel height on this device
> + * @min_width: minimum fb pixel width on this device
> + * @min_height: minimum fb pixel height on this device
> + * @max_width: maximum fb pixel width on this device
> + * @max_height: maximum fb pixel height on this device
>   * @funcs: core driver provided mode setting functions
>   * @fb_base: base address of the framebuffer
>   * @poll_enabled: track polling support for this device
> -- 
> 2.16.4
> 
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