drm: Nuke mode->hsync

Let's just calculate the hsync rate on demand. No point in wasting
space storing it and risking the cached value getting out of sync
with reality.

v2: Move drm_mode_hsync() next to its only users
    Drop the TODO
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com> #v1
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428171940.19552-2-ville.syrjala@linux.intel.com

Documentation/gpu/todo.rst

@@ -347,18 +347,6 @@ Contact: Sean Paul
 
 Level: Starter
 
-Remove drm_display_mode.hsync
------------------------------
-
-We have drm_mode_hsync() to calculate this from hsync_start/end, since drivers
-shouldn't/don't use this, remove this member to avoid any temptations to use it
-in the future. If there is any debug code using drm_display_mode.hsync, convert
-it to use drm_mode_hsync() instead.
-
-Contact: Sean Paul
-
-Level: Starter
-
 connector register/unregister fixes
 -----------------------------------
 

drivers/gpu/drm/drm_edid.c

@@ -2380,6 +2380,14 @@ bad_std_timing(u8 a, u8 b)
 	       (a == 0x20 && b == 0x20);
 }
 
+static int drm_mode_hsync(const struct drm_display_mode *mode)
+{
+	if (mode->htotal <= 0)
+		return 0;
+
+	return DIV_ROUND_CLOSEST(mode->clock, mode->htotal);
+}
+
 /**
  * drm_mode_std - convert standard mode info (width, height, refresh) into mode
  * @connector: connector of for the EDID block

drivers/gpu/drm/drm_modes.c

@@ -747,32 +747,6 @@ void drm_mode_set_name(struct drm_display_mode *mode)
 }
 EXPORT_SYMBOL(drm_mode_set_name);
 
-/**
- * drm_mode_hsync - get the hsync of a mode
- * @mode: mode
- *
- * Returns:
- * @modes's hsync rate in kHz, rounded to the nearest integer. Calculates the
- * value first if it is not yet set.
- */
-int drm_mode_hsync(const struct drm_display_mode *mode)
-{
-	unsigned int calc_val;
-
-	if (mode->hsync)
-		return mode->hsync;
-
-	if (mode->htotal <= 0)
-		return 0;
-
-	calc_val = (mode->clock * 1000) / mode->htotal; /* hsync in Hz */
-	calc_val += 500;				/* round to 1000Hz */
-	calc_val /= 1000;				/* truncate to kHz */
-
-	return calc_val;
-}
-EXPORT_SYMBOL(drm_mode_hsync);
-
 /**
  * drm_mode_vrefresh - get the vrefresh of a mode
  * @mode: mode

drivers/gpu/drm/i915/display/intel_display.c

@@ -8891,7 +8891,6 @@ void intel_mode_from_pipe_config(struct drm_display_mode *mode,
 
 	mode->clock = pipe_config->hw.adjusted_mode.crtc_clock;
 
-	mode->hsync = drm_mode_hsync(mode);
 	mode->vrefresh = drm_mode_vrefresh(mode);
 	drm_mode_set_name(mode);
 }

include/drm/drm_modes.h

@@ -390,16 +390,6 @@ struct drm_display_mode {
 	 */
 	int vrefresh;
 
-	/**
-	 * @hsync:
-	 *
-	 * Horizontal refresh rate, for debug output in human readable form. Not
-	 * used in a functional way.
-	 *
-	 * This value is in kHz.
-	 */
-	int hsync;
-
 	/**
 	 * @picture_aspect_ratio:
 	 *
@@ -493,7 +483,6 @@ int of_get_drm_display_mode(struct device_node *np,
 			    int index);
 
 void drm_mode_set_name(struct drm_display_mode *mode);
-int drm_mode_hsync(const struct drm_display_mode *mode);
 int drm_mode_vrefresh(const struct drm_display_mode *mode);
 void drm_mode_get_hv_timing(const struct drm_display_mode *mode,
 			    int *hdisplay, int *vdisplay);