[Intel-gfx] [Patch] DRM/I915: Calculate the DVO relative offset in LVDS data entry to get the DVO timing

[yakui.zhao at intel.com]

From: Zhao Yakui <yakui.zhao at intel.com>

    Now the DVO timing in LVDS data entry is obtained by using the
following step:
    a. get the entry size for every LVDS panel data
    b. Get the LVDS fp entry for the preferred panel type
    c. get the DVO timing by using entry->dvo_timing

    In our driver the entry->dvo_timing is related with the size of
lvds_fp_timing. For example: the size is 46.

    But it seems that the size of lvds_fp_timing varies on the differnt
platform. In such case we will get the incorrect DVO timing entry because of
the incorrect DVO offset in LVDS panel data entry.

Calculate the DVO timing offset in LVDS data entry to get the DVO timing
    a. get the DVO timing offset in the LVDS fp data entry by using the
pointer definition in LVDS data ptr
    b. get the LVDS data entry
    c. get the DVO timing by adding the DVO timing offset to data entry

https://bugs.freedesktop.org/show_bug.cgi?id=22787

Signed-off-by: Zhao Yakui <yakui.zhao at intel.com>
---
 drivers/gpu/drm/i915/intel_bios.c |   18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

Index: linux-2.6/drivers/gpu/drm/i915/intel_bios.c
===================================================================
--- linux-2.6.orig/drivers/gpu/drm/i915/intel_bios.c	2009-07-23 09:23:36.000000000 +0800
+++ linux-2.6/drivers/gpu/drm/i915/intel_bios.c	2009-07-24 10:52:40.000000000 +0800
@@ -104,7 +104,7 @@
 	struct bdb_lvds_lfp_data_entry *entry;
 	struct lvds_dvo_timing *dvo_timing;
 	struct drm_display_mode *panel_fixed_mode;
-	int lfp_data_size;
+	int lfp_data_size, dvo_timing_offset;
 
 	/* Defaults if we can't find VBT info */
 	dev_priv->lvds_dither = 0;
@@ -133,14 +133,16 @@
 	entry = (struct bdb_lvds_lfp_data_entry *)
 		((uint8_t *)lvds_lfp_data->data + (lfp_data_size *
 						   lvds_options->panel_type));
+	dvo_timing_offset = lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset -
+		lvds_lfp_data_ptrs->ptr[0].fp_timing_offset;
 
-	/* On IGDNG mobile, LVDS data block removes panel fitting registers.
-	   So dec 2 dword from dvo_timing offset */
-	if (IS_IGDNG(dev))
-		dvo_timing = (struct lvds_dvo_timing *)
-					((u8 *)&entry->dvo_timing - 8);
-	else
-		dvo_timing = &entry->dvo_timing;
+	/*
+	 * the size of fp_timing varies on the different platform.
+	 * So calculate the DVO timing relative offset in LVDS data
+	 * entry to get the DVO timing entry
+	 */
+	dvo_timing = (struct lvds_dvo_timing *)
+			((unsigned char *)entry + dvo_timing_offset);
 
 	panel_fixed_mode = kzalloc(sizeof(*panel_fixed_mode), GFP_KERNEL);