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Commit d1fcea6a authored by Zhao Yakui's avatar Zhao Yakui Committed by Eric Anholt
Browse files

drm/i915: Check whether the LVDS downclock is found in VBT 



Enumerate the LVDS panel timing info entry list in VBT to check whether
the LVDS downclock is found. If found, the downclock is also used to switch
dynamically between low and high frequency for LVDS.

Signed-off-by: default avatarZhao Yakui <yakui.zhao@intel.com>
Acked-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
parent 18f9ed12

drivers/gpu/drm/i915/intel_bios.c

+42 −0
Original line number Diff line number Diff line
@@ -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;

}