@@ -93,6 +93,11 @@ struct detailed_mode_closure {
int modes;
};
+struct edid_support_rb_closure {
+ struct edid *edid;
+ u8 support_rb;
+};
+
#define LEVEL_DMT 0
#define LEVEL_GTF 1
#define LEVEL_GTF2 2
@@ -2018,22 +2023,31 @@ struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
is_rb(struct detailed_timing *t, void *data)
{
u8 *r = (u8 *)t;
- if (r[3] == EDID_DETAIL_MONITOR_RANGE)
- if (r[15] & 0x10)
- *(bool *)data = true;
+ struct edid_support_rb_closure *closure = data;
+ struct edid *edid = closure->edid;
+
+ if (!r[0] && !r[1] && !r[2] && r[3] == EDID_DETAIL_MONITOR_RANGE) {
+ if (edid->features & BIT(0) && r[10] == BIT(2))
+ closure->support_rb = (r[15] & 0x10) ? 1 : 0;
+ }
}
/* EDID 1.4 defines this explicitly. For EDID 1.3, we guess, badly. */
static bool
drm_monitor_supports_rb(struct edid *edid)
{
+ struct edid_support_rb_closure closure = {
+ .edid = edid,
+ .support_rb = -1,
+ };
+
if (edid->revision >= 4) {
- bool ret = false;
- drm_for_each_detailed_block((u8 *)edid, is_rb, &ret);
- return ret;
+ drm_for_each_detailed_block((u8 *)edid, is_rb, &closure);
+ if (closure.support_rb >= 0)
+ return closure.support_rb;
}
- return ((edid->input & DRM_EDID_INPUT_DIGITAL) != 0);
+ return true;
}
static void
According to VESA ENHANCED EXTENDED DISPLAY IDENTIFICATION DATA STANDARD (Defines EDID Structure Version 1, Revision 4) page: 39 How to determine whether the monitor support RB timing or not? EDID 1.4 First: read detailed timing descriptor and make sure byte0 = 0, byte1 = 0, byte2 = 0 and byte3 = 0xFD Second: read detailed timing descriptor byte10 = 0x04 and EDID byte18h bit0 = 1 Third: if EDID byte18h bit0 == 1 && byte10 == 0x04, then we can check byte15, if byte15 bit4 =1 is support RB if EDID byte18h bit0 != 1 || byte10 != 0x04, then byte15 can not be used The linux code is_rb function not follow the VESA's rule EDID 1.3 LCD flat panels do not require long blanking intervals as a retrace period so default support reduced-blanking timings. Signed-off-by: Allen Chen <allen.chen@ite.com.tw> --- drivers/gpu/drm/drm_edid.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-)