drm/i915/bios: Copy the whole MIPI sequence block

Turns out the MIPI sequence block version number and
new block size fields are considered part of the block
header and are not included in the reported new block size
field itself. Bump up the block size appropriately so that
we'll copy over the last five bytes of the block as well.

For this particular machine those last five bytes included
parts of the GPIO op for the backlight on sequence, causing
the backlight no longer to turn back on:

 		Sequence 6 - MIPI_SEQ_BACKLIGHT_ON
 			Delay: 20000 us
-			GPIO index 0, number 0, set 0 (0x00)
+			GPIO index 1, number 70, set 1 (0x01)

Cc: stable@vger.kernel.org
Fixes: e163cfb4c96d ("drm/i915/bios: Make copies of VBT data blocks")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6652
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220829135834.8585-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 5765643..9c8eeca 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -479,6 +479,13 @@ init_bdb_block(struct drm_i915_private *i915,
 
        block_size = get_blocksize(block);
 
+       /*
+        * Version number and new block size are considered
+        * part of the header for MIPI sequenece block v3+.
+        */
+       if (section_id == BDB_MIPI_SEQUENCE && *(const u8 *)block >= 3)
+               block_size += 5;
+
        entry = kzalloc(struct_size(entry, data, max(min_size, block_size) + 3),
                        GFP_KERNEL);
        if (!entry) {