VESA Enhanced EDID Standard does not clearly describe how display
panel vendors should setup the Sync Signal Defintions (bit 4 & 3) in
the Detailed Timing Definition (relative offset 17, absolute offset
47h[+18]) for Digital Video Signal Interfaces (bit 7 at offset 14h).
In practice many eDP panels which using a Digital Video Signal
Interfaces (bit 7 at offset 14h == 1) are leaving the Sync Signal
Defintions at offset 47h[+18] blank 0x00, which would mean concerned
with the VESA Standard [1] that they are using "Analog Composite
Sync".
Fix: Just detect Analog Sync Signal if an Analog Video Signal
Interface (bit 7 at offset 14h == 0) is in use. Just detect
Digital Sync Signal if an Digital Video Signal Interface is in
use.
Reference: [1] VESA Enhanced EDID Standard, Release A, Rev.2, Page 35
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8789
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8146
Signed-off-by: Dirk Lehmann <deve...@dj-l.de>
---
drivers/gpu/drm/drm_edid.c | 74 ++++++++++++++++++++++++++++++++------
include/drm/drm_edid.h | 12 +++++--
2 files changed, 73 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 1f470968ed14..6afdc34e55ce 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3437,6 +3437,7 @@ static struct drm_display_mode *drm_mode_detailed(struct
drm_connector *connecto
const struct drm_display_info *info = &connector->display_info;
struct drm_device *dev = connector->dev;
struct drm_display_mode *mode;
+ const struct edid *edid = drm_edid->edid;
const struct detailed_pixel_timing *pt = &timing->data.pixel_data;
unsigned hactive = (pt->hactive_hblank_hi & 0xf0) << 4 | pt->hactive_lo;
unsigned vactive = (pt->vactive_vblank_hi & 0xf0) << 4 | pt->vactive_lo;
@@ -3456,10 +3457,6 @@ static struct drm_display_mode *drm_mode_detailed(struct
drm_connector *connecto
connector->base.id, connector->name);
return NULL;
}
- if (!(pt->misc & DRM_EDID_PT_SEPARATE_SYNC)) {
- drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Composite sync not
supported\n",
- connector->base.id, connector->name);
- }
/* it is incorrect if hsync/vsync width is zero */
if (!hsync_pulse_width || !vsync_pulse_width) {
@@ -3505,11 +3502,68 @@ static struct drm_display_mode
*drm_mode_detailed(struct drm_connector *connecto
if (info->quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
mode->flags |= DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC;
+ } else if (edid->input & DRM_EDID_INPUT_DIGITAL) {
+ /* !info->quirks && edid->input == DIGITAL */
+ switch (pt->misc & DRM_EDID_PT_SYNC_MASK) {
+ /* VESA Enhanced EDID Standard, Release A, Rev.2, Page 35
+ *
+ * CASE DRM_EDID_PT_ANALOG_CSYNC:
+ *
+ * (pt->misc & DRM_EDID_PT_SYNC_MASK == 0x00) means
+ * "Analog Composite Sync" as described in VESA
+ * Standard. But many digital display panels without
+ * composite sync are also using 0x00 here.
+ *
+ * Therefore use DEFAULT: as we are currently on an
+ * digital video signal interface.
+ */
+ case DRM_EDID_PT_DIGITAL_CSYNC:
+ drm_dbg_kms(dev,
+ "[CONNECTOR:%d:%s] Digital composite sync!\n",
+ connector->base.id, connector->name);
+ mode->flags |= DRM_MODE_FLAG_CSYNC;
+ mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
+ DRM_MODE_FLAG_PCSYNC : DRM_MODE_FLAG_NCSYNC;
+ break;
+ case DRM_EDID_PT_DIGITAL_SEPARATE_SYNC:
+ drm_dbg_kms(dev,
+ "[CONNECTOR:%d:%s] Digital seperate sync!\n",
+ connector->base.id, connector->name);
+ goto digital_default;
+ break; /* Missing BREAK throws a compiler warning */
+ default:
+digital_default:
+ mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
+ DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
+ mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
+ DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
+ break;
+ }
} else {
- mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
- DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
- mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
- DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
+ /* !info->quirks && edid->input == ANALOG */
+ switch (pt->misc & DRM_EDID_PT_SYNC_MASK) {
+ /* VESA Enhanced EDID Standard, Release A, Rev.2, Page 35
+ *
+ * CASE DRM_EDID_PT_ANALOG_CSYNC:
+ *
+ * (pt->misc & DRM_EDID_PT_SYNC_MASK == 0x00) for
+ * "Analog Composite Sync" is possible here, as we are
+ * currently on an analog video signal interface.
+ */
+ case DRM_EDID_PT_ANALOG_CSYNC:
+ case DRM_EDID_PT_BIPOLAR_ANALOG_CSYNC:
+ drm_dbg_kms(dev,
+ "[CONNECTOR:%d:%s] Analog composite sync!\n",
+ connector->base.id, connector->name);
+ mode->flags |= DRM_MODE_FLAG_CSYNC |
DRM_MODE_FLAG_NCSYNC;
+ break;
+ default:
+ mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
+ DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
+ mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
+ DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
+ break;
+ }
}
set_size:
@@ -3522,8 +3576,8 @@ static struct drm_display_mode *drm_mode_detailed(struct
drm_connector *connecto
}
if (info->quirks & EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE) {
- mode->width_mm = drm_edid->edid->width_cm * 10;
- mode->height_mm = drm_edid->edid->height_cm * 10;
+ mode->width_mm = edid->width_cm * 10;
+ mode->height_mm = edid->height_cm * 10;
}
mode->type = DRM_MODE_TYPE_DRIVER;
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 48e93f909ef6..169755d3de19 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -61,9 +61,15 @@ struct std_timing {
u8 vfreq_aspect;
} __attribute__((packed));
-#define DRM_EDID_PT_HSYNC_POSITIVE (1 << 1)
-#define DRM_EDID_PT_VSYNC_POSITIVE (1 << 2)
-#define DRM_EDID_PT_SEPARATE_SYNC (3 << 3)
+#define DRM_EDID_PT_SYNC_MASK (3 << 3)
+# define DRM_EDID_PT_ANALOG_CSYNC (0 << 3)
+# define DRM_EDID_PT_BIPOLAR_ANALOG_CSYNC (1 << 3)
+# define DRM_EDID_PT_DIGITAL_CSYNC (2 << 3)
+# define DRM_EDID_PT_CSYNC_ON_RGB (1 << 1) /* analog csync only */
+# define DRM_EDID_PT_CSYNC_SERRATE (1 << 2)
+# define DRM_EDID_PT_DIGITAL_SEPARATE_SYNC (3 << 3)
+# define DRM_EDID_PT_HSYNC_POSITIVE (1 << 1) /* also digital csync */
+# define DRM_EDID_PT_VSYNC_POSITIVE (1 << 2)
#define DRM_EDID_PT_STEREO (1 << 5)
#define DRM_EDID_PT_INTERLACED (1 << 7)
--
2.40.1
