From 20e29dd98823a19ec3e38fbdcf86b6983268c657 Mon Sep 17 00:00:00 2001
From: Liu Ying <victor.liu@nxp.com>
Date: Thu, 14 Jun 2018 17:41:58 +0800
Subject: [PATCH] MLK-18507 drm/bridge: it6263: Filter out known bad display
modes
It turns out the following display modes are not well supported
by the bridge - 1600x900@60, 1280x1024@60, 1280x720@30/25/24
and 1152x864@75. Fortunately, they are not that widely used.
So, list them as the known bad display modes and filter them out
in ->mode_valid().
Signed-off-by: Liu Ying <victor.liu@nxp.com>
(cherry picked from commit c44ed03cf3b85d7f5bc8325ffeec9fd07f66aa87)
---
drivers/gpu/drm/bridge/it6263.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/gpu/drm/bridge/it6263.c b/drivers/gpu/drm/bridge/it6263.c
index f309380a0be11c..2bed01900a269d 100644
--- a/drivers/gpu/drm/bridge/it6263.c
+++ b/drivers/gpu/drm/bridge/it6263.c
@@ -335,6 +335,21 @@ struct it6263 {
bool split_mode;
};
+struct it6263_minimode {
+ int hdisplay;
+ int vdisplay;
+ int vrefresh;
+};
+
+static const struct it6263_minimode it6263_bad_mode_db[] = {
+ {1600, 900, 60},
+ {1280, 1024, 60},
+ {1280, 720, 30},
+ {1280, 720, 25},
+ {1280, 720, 24},
+ {1152, 864, 75},
+};
+
static inline struct it6263 *bridge_to_it6263(struct drm_bridge *bridge)
{
return container_of(bridge, struct it6263, bridge);
@@ -507,9 +522,20 @@ static int it6263_get_modes(struct drm_connector *connector)
enum drm_mode_status it6263_mode_valid(struct drm_connector *connector,
struct drm_display_mode *mode)
{
+ const struct it6263_minimode *m;
+ int i, vrefresh = drm_mode_vrefresh(mode);
+
if (mode->clock > 150000)
return MODE_CLOCK_HIGH;
+ for (i = 0; i < ARRAY_SIZE(it6263_bad_mode_db); i++) {
+ m = &it6263_bad_mode_db[i];
+ if ((mode->hdisplay == m->hdisplay) &&
+ (mode->vdisplay == m->vdisplay) &&
+ (vrefresh == m->vrefresh))
+ return MODE_BAD;
+ }
+
return MODE_OK;
}
--
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