[RFC v3 07/12] drm/modes: Add drm_umode_equal()

[Daniel Vetter]

On Thu, Feb 22, 2018 at 09:06:48PM +0100, Noralf Trønnes wrote:
> Add a way to check if userspace modes are equal. Useful for in-kernel
> clients. Also export drm_mode_convert_umode().
> 
> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>

Assuming we don't use the KMS ioctls for in-kernel clients I guess we
don't need this here either?
-Daniel

> ---
>  drivers/gpu/drm/drm_modes.c | 50 +++++++++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_modes.h     |  2 ++
>  2 files changed, 52 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index 5a8033fda4e3..0e39164f15aa 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -1631,6 +1631,56 @@ int drm_mode_convert_umode(struct drm_device *dev,
>  out:
>  	return ret;
>  }
> +EXPORT_SYMBOL(drm_mode_convert_umode);
> +
> +/**
> + * drm_umode_equal - test modeinfo modes for equality
> + * @mode1: first mode
> + * @mode2: second mode
> + *
> + * Check to see if @mode1 and @mode2 are equivalent.
> + *
> + * Returns:
> + * True if the modes are equal, false otherwise.
> + */
> +bool drm_umode_equal(const struct drm_mode_modeinfo *mode1,
> +		     const struct drm_mode_modeinfo *mode2)
> +{
> +	if (!mode1 && !mode2)
> +		return true;
> +
> +	if (!mode1 || !mode2)
> +		return false;
> +
> +	/* do clock check convert to PICOS so fb modes get matched the same */
> +	if (mode1->clock && mode2->clock) {
> +		if (KHZ2PICOS(mode1->clock) != KHZ2PICOS(mode2->clock))
> +			return false;
> +	} else if (mode1->clock != mode2->clock) {
> +		return false;
> +	}
> +
> +	if ((mode1->flags & DRM_MODE_FLAG_3D_MASK) !=
> +	    (mode2->flags & DRM_MODE_FLAG_3D_MASK))
> +		return false;
> +
> +	if (mode1->hdisplay == mode2->hdisplay &&
> +	    mode1->hsync_start == mode2->hsync_start &&
> +	    mode1->hsync_end == mode2->hsync_end &&
> +	    mode1->htotal == mode2->htotal &&
> +	    mode1->hskew == mode2->hskew &&
> +	    mode1->vdisplay == mode2->vdisplay &&
> +	    mode1->vsync_start == mode2->vsync_start &&
> +	    mode1->vsync_end == mode2->vsync_end &&
> +	    mode1->vtotal == mode2->vtotal &&
> +	    mode1->vscan == mode2->vscan &&
> +	    (mode1->flags & ~DRM_MODE_FLAG_3D_MASK) ==
> +	     (mode2->flags & ~DRM_MODE_FLAG_3D_MASK))
> +		return true;
> +
> +	return false;
> +}
> +EXPORT_SYMBOL(drm_umode_equal);
>  
>  /**
>   * drm_mode_is_420_only - if a given videomode can be only supported in YCBCR420
> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
> index 0d310beae6af..05e73ca4f2ae 100644
> --- a/include/drm/drm_modes.h
> +++ b/include/drm/drm_modes.h
> @@ -447,6 +447,8 @@ void drm_mode_convert_to_umode(struct drm_mode_modeinfo *out,
>  int drm_mode_convert_umode(struct drm_device *dev,
>  			   struct drm_display_mode *out,
>  			   const struct drm_mode_modeinfo *in);
> +bool drm_umode_equal(const struct drm_mode_modeinfo *mode1,
> +		     const struct drm_mode_modeinfo *mode2);
>  void drm_mode_probed_add(struct drm_connector *connector, struct drm_display_mode *mode);
>  void drm_mode_debug_printmodeline(const struct drm_display_mode *mode);
>  bool drm_mode_is_420_only(const struct drm_display_info *display,
> -- 
> 2.15.1
> 

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