@@ -114,6 +114,8 @@ parse_lfp_panel_data(struct drm_i915_private *dev_priv,
struct lvds_dvo_timing *dvo_timing;
struct drm_display_mode *panel_fixed_mode;
int lfp_data_size, dvo_timing_offset;
+ int i, temp_downclock;
+ struct drm_display_mode *temp_mode;
/* Defaults if we can't find VBT info */
dev_priv->lvds_dither = 0;
@@ -162,6 +164,46 @@ parse_lfp_panel_data(struct drm_i915_private *dev_priv,
DRM_DEBUG_KMS("Found panel mode in BIOS VBT tables:\n");
drm_mode_debug_printmodeline(panel_fixed_mode);
+ temp_mode = kzalloc(sizeof(*temp_mode), GFP_KERNEL);
+ temp_downclock = panel_fixed_mode->clock;
+ /*
+ * enumerate the LVDS panel timing info entry in VBT to check whether
+ * the LVDS downclock is found.
+ */
+ for (i = 0; i < 16; i++) {
+ entry = (struct bdb_lvds_lfp_data_entry *)
+ ((uint8_t *)lvds_lfp_data->data + (lfp_data_size * i));
+ dvo_timing = (struct lvds_dvo_timing *)
+ ((unsigned char *)entry + dvo_timing_offset);
+
+ fill_detail_timing_data(temp_mode, dvo_timing);
+
+ if (temp_mode->hdisplay == panel_fixed_mode->hdisplay &&
+ temp_mode->hsync_start == panel_fixed_mode->hsync_start &&
+ temp_mode->hsync_end == panel_fixed_mode->hsync_end &&
+ temp_mode->htotal == panel_fixed_mode->htotal &&
+ temp_mode->vdisplay == panel_fixed_mode->vdisplay &&
+ temp_mode->vsync_start == panel_fixed_mode->vsync_start &&
+ temp_mode->vsync_end == panel_fixed_mode->vsync_end &&
+ temp_mode->vtotal == panel_fixed_mode->vtotal &&
+ temp_mode->clock < temp_downclock) {
+ /*
+ * downclock is already found. But we expect
+ * to find the lower downclock.
+ */
+ temp_downclock = temp_mode->clock;
+ }
+ /* clear it to zero */
+ memset(temp_mode, 0, sizeof(*temp_mode));
+ }
+ kfree(temp_mode);
+ if (temp_downclock < panel_fixed_mode->clock) {
+ dev_priv->lvds_downclock_avail = 1;
+ dev_priv->lvds_downclock = temp_downclock;
+ DRM_DEBUG_KMS("LVDS downclock is found in VBT. ",
+ "Normal Clock %dKHz, downclock %dKHz\n",
+ temp_downclock, panel_fixed_mode->clock);
+ }
return;
}