drm: Add drm_mode_equal_no_clocks()

drm_mode_equal_no_clocks() is like drm_mode_equal() except it doesn't
compare the clock or vrefresh values. drm_mode_equal() is now
implemented by first doing the clock checks, and then calling
drm_mode_equal_no_clocks().

v2: Add missing EXPORT_SYMBOL()
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_modes.c

@@ -848,6 +848,26 @@ bool drm_mode_equal(const struct drm_display_mode *mode1, const struct drm_displ
 	} else if (mode1->clock != mode2->clock)
 		return false;
 
+	return drm_mode_equal_no_clocks(mode1, mode2);
+}
+EXPORT_SYMBOL(drm_mode_equal);
+
+/**
+ * drm_mode_equal_no_clocks - test modes for equality
+ * @mode1: first mode
+ * @mode2: second mode
+ *
+ * LOCKING:
+ * None.
+ *
+ * Check to see if @mode1 and @mode2 are equivalent, but
+ * don't check the pixel clocks.
+ *
+ * RETURNS:
+ * True if the modes are equal, false otherwise.
+ */
+bool drm_mode_equal_no_clocks(const struct drm_display_mode *mode1, const struct drm_display_mode *mode2)
+{
 	if (mode1->hdisplay == mode2->hdisplay &&
 	    mode1->hsync_start == mode2->hsync_start &&
 	    mode1->hsync_end == mode2->hsync_end &&
@@ -863,7 +883,7 @@ bool drm_mode_equal(const struct drm_display_mode *mode1, const struct drm_displ
 
 	return false;
 }
-EXPORT_SYMBOL(drm_mode_equal);
+EXPORT_SYMBOL(drm_mode_equal_no_clocks);
 
 /**
  * drm_mode_validate_size - make sure modes adhere to size constraints

include/drm/drm_crtc.h

@@ -922,6 +922,7 @@ extern void drm_mode_config_reset(struct drm_device *dev);
 extern void drm_mode_config_cleanup(struct drm_device *dev);
 extern void drm_mode_set_name(struct drm_display_mode *mode);
 extern bool drm_mode_equal(const struct drm_display_mode *mode1, const struct drm_display_mode *mode2);
+extern bool drm_mode_equal_no_clocks(const struct drm_display_mode *mode1, const struct drm_display_mode *mode2);
 extern int drm_mode_width(const struct drm_display_mode *mode);
 extern int drm_mode_height(const struct drm_display_mode *mode);