[PATCH 3/9] drm/edid: use struct detailed_timing member access in is_rb()

[Jani Nikula]

Use struct detailed_timing member access instead of direct offsets to
avoid casting.

Use BUILD_BUG_ON() for sanity check.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>

---

Note: Why can we use range.formula.cvt.flags directly in is_rb() while
gtf2 functions check for range.flags == 0x02 first to ensure it's gtf2?
---
 drivers/gpu/drm/drm_edid.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 48707eef1dc2..5396fa78e864 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2405,15 +2405,17 @@ drm_for_each_detailed_block(u8 *raw_edid, detailed_cb *cb, void *closure)
 }
 
 static void
-is_rb(struct detailed_timing *t, void *data)
+is_rb(struct detailed_timing *timing, void *data)
 {
-	u8 *r = (u8 *)t;
+	bool *res = data;
 
-	if (!is_display_descriptor(t, EDID_DETAIL_MONITOR_RANGE))
+	if (!is_display_descriptor(timing, EDID_DETAIL_MONITOR_RANGE))
 		return;
 
-	if (r[15] & 0x10)
-		*(bool *)data = true;
+	BUILD_BUG_ON(offsetof(typeof(*timing), data.other_data.data.range.formula.cvt.flags) != 15);
+
+	if (timing->data.other_data.data.range.formula.cvt.flags & 0x10)
+		*res = true;
 }
 
 /* EDID 1.4 defines this explicitly.  For EDID 1.3, we guess, badly. */
-- 
2.30.2