[Intel-gfx] [PATCH] drm/i915: fix LFP data fetch

[Jesse Barnes]

Apparently the proper way to do this is to use the LFP data pointer
block to figure out the LFP data block entry size, then use that plus
the panel index to calculate an offset into the LFP data block array.

Similar fix has already been pushed to the 2D driver to fix fdo bug
#19450.  Wider testing appreciated (though this fix has also been
applied to the VBIOS reader, and things look sane).

Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 754dd22..c350d56 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -99,9 +99,11 @@ parse_lfp_panel_data(struct drm_i915_private *dev_priv,
 {
 	struct bdb_lvds_options *lvds_options;
 	struct bdb_lvds_lfp_data *lvds_lfp_data;
+	struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs;
 	struct bdb_lvds_lfp_data_entry *entry;
 	struct lvds_dvo_timing *dvo_timing;
 	struct drm_display_mode *panel_fixed_mode;
+	int lfp_data_size;
 
 	/* Defaults if we can't find VBT info */
 	dev_priv->lvds_dither = 0;
@@ -119,9 +121,17 @@ parse_lfp_panel_data(struct drm_i915_private *dev_priv,
 	if (!lvds_lfp_data)
 		return;
 
+	lvds_lfp_data_ptrs = find_section(bdb, BDB_LVDS_LFP_DATA_PTRS);
+	if (!lvds_lfp_data_ptrs)
+		return;
+
 	dev_priv->lvds_vbt = 1;
 
-	entry = &lvds_lfp_data->data[lvds_options->panel_type];
+	lfp_data_size = lvds_lfp_data_ptrs->ptr[1].dvo_timing_offset -
+		lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset;
+	entry = (struct bdb_lvds_lfp_data_entry *)
+		((uint8_t *)lvds_lfp_data->data + (lfp_data_size *
+						   lvds_options->panel_type));
 	dvo_timing = &entry->dvo_timing;
 
 	panel_fixed_mode = drm_calloc(1, sizeof(*panel_fixed_mode),