From 6c861a16a39a7d61c6d72a39e65112c0a6f79508 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 8 Jun 2022 10:50:32 +0300
Subject: drm/edid: abstract cea data block collection size
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Git-commit: 11a8d095d86854bbc8697525f2c543de36bf5804
Patch-mainline: v6.0-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849
Add a function to get the cea data block collection size.
Cc: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5339ab3249400a3c41001967e7ff2611b58e0425.1654674560.git.jani.nikula@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/drm_edid.c | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index c57f6333ea7d..002816509fc8 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4482,6 +4482,20 @@ __cea_db_iter_current_block(const struct cea_db_iter *iter)
return NULL;
}
+/*
+ * References:
+ * - CTA-861-H section 7.3.3 CTA Extension Version 3
+ */
+static int cea_db_collection_size(const u8 *cta)
+{
+ u8 d = cta[2];
+
+ if (d < 4 || d > 127)
+ return 0;
+
+ return d - 4;
+}
+
/*
* References:
* - VESA E-EDID v1.4
@@ -4492,15 +4506,19 @@ static const void *__cea_db_iter_edid_next(struct cea_db_iter *iter)
const u8 *ext;
drm_edid_iter_for_each(ext, &iter->edid_iter) {
+ int size;
+
/* Only support CTA Extension revision 3+ */
if (ext[0] != CEA_EXT || cea_revision(ext) < 3)
continue;
- iter->index = 4;
- iter->end = ext[2];
- if (iter->end < 4 || iter->end > 127)
+ size = cea_db_collection_size(ext);
+ if (!size)
continue;
+ iter->index = 4;
+ iter->end = iter->index + size;
+
return ext;
}
--
2.38.1