drm/i915/bios: Fixup h/vsync_end instead of h/vtotal

We have the same h/vsync_end vs. h/vtotal quirk in the VBT parser
that was also present in EDID parser. Adjust the VBT parser the
same way as was done for hte EDID parser to fixup h/vsync_end
instead of h/vtotal. While I'm not currently aware of any machines
that need this for the VBT it seems prudent to keep both parsers
in sync.

And while at it let's add some debugs here as well. A bit
lackluster but didn't feel like plumbing the connector all
the way down at this time.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230920211934.14920-2-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -521,7 +521,8 @@ static void init_bdb_blocks(struct drm_i915_private *i915,
 }
 
 static void
-fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
+fill_detail_timing_data(struct drm_i915_private *i915,
+			struct drm_display_mode *panel_fixed_mode,
 			const struct lvds_dvo_timing *dvo_timing)
 {
 	panel_fixed_mode->hdisplay = (dvo_timing->hactive_hi << 8) |
@@ -561,11 +562,17 @@ fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
 	panel_fixed_mode->height_mm = (dvo_timing->vimage_hi << 8) |
 		dvo_timing->vimage_lo;
 
-	/* Some VBTs have bogus h/vtotal values */
-	if (panel_fixed_mode->hsync_end > panel_fixed_mode->htotal)
-		panel_fixed_mode->htotal = panel_fixed_mode->hsync_end + 1;
-	if (panel_fixed_mode->vsync_end > panel_fixed_mode->vtotal)
-		panel_fixed_mode->vtotal = panel_fixed_mode->vsync_end + 1;
+	/* Some VBTs have bogus h/vsync_end values */
+	if (panel_fixed_mode->hsync_end > panel_fixed_mode->htotal) {
+		drm_dbg_kms(&i915->drm, "reducing hsync_end %d->%d\n",
+			    panel_fixed_mode->hsync_end, panel_fixed_mode->htotal);
+		panel_fixed_mode->hsync_end = panel_fixed_mode->htotal;
+	}
+	if (panel_fixed_mode->vsync_end > panel_fixed_mode->vtotal) {
+		drm_dbg_kms(&i915->drm, "reducing vsync_end %d->%d\n",
+			    panel_fixed_mode->vsync_end, panel_fixed_mode->vtotal);
+		panel_fixed_mode->vsync_end = panel_fixed_mode->vtotal;
+	}
 
 	drm_mode_set_name(panel_fixed_mode);
 }
@@ -849,7 +856,7 @@ parse_lfp_panel_dtd(struct drm_i915_private *i915,
 	if (!panel_fixed_mode)
 		return;
 
-	fill_detail_timing_data(panel_fixed_mode, panel_dvo_timing);
+	fill_detail_timing_data(i915, panel_fixed_mode, panel_dvo_timing);
 
 	panel->vbt.lfp_lvds_vbt_mode = panel_fixed_mode;
 
@@ -1134,7 +1141,7 @@ parse_sdvo_panel_data(struct drm_i915_private *i915,
 	if (!panel_fixed_mode)
 		return;
 
-	fill_detail_timing_data(panel_fixed_mode, &dtds->dtds[index]);
+	fill_detail_timing_data(i915, panel_fixed_mode, &dtds->dtds[index]);
 
 	panel->vbt.sdvo_lvds_vbt_mode = panel_fixed_mode;