[PATCH v4 2/2] drm/dp: Add function to parse EDID descriptors for adaptive sync limits

Manasi Navare
2020-03-06T01:41:26Z

Adaptive Sync is a VESA feature so add a DRM core helper to parse
the EDID's detailed descritors to obtain the adaptive sync monitor range.
Store this info as part fo drm_display_info so it can be used
across all drivers.
This part of the code is stripped out of amdgpu's function
amdgpu_dm_update_freesync_caps() to make it generic and be used
across all DRM drivers

v4:
* Use is_display_descriptor() (Ville)
* Name the monitor range flags (Ville)
v3:
* Remove the edid parsing restriction for just DP (Nicholas)
* Use drm_for_each_detailed_block (Ville)
* Make the drm_get_adaptive_sync_range function static (Harry, Jani)
v2:
* Change vmin and vmax to use u8 (Ville)
* Dont store pixel clock since that is just a max dotclock
and not related to VRR mode (Manasi)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Clinton A Taylor <clinton.a.taylor@intel.com>
Cc: Kazlauskas Nicholas <Nicholas.Kazlauskas@amd.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
---
drivers/gpu/drm/drm_edid.c | 44 +++++++++++++++++++++++++++++++++++++
include/drm/drm_connector.h | 22 +++++++++++++++++++
2 files changed, 66 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index ad41764a4ebe..61ed544d9535 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4938,6 +4938,47 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
}
}

+static
+void get_adaptive_sync_range(struct detailed_timing *timing,
+ void *info_adaptive_sync)
+{
+ struct drm_adaptive_sync_info *adaptive_sync = info_adaptive_sync;
+ const struct detailed_non_pixel *data = &timing->data.other_data;
+ const struct detailed_data_monitor_range *range = &data->data.range;
+
+ if (!is_display_descriptor((const u8 *)timing, EDID_DETAIL_MONITOR_RANGE))
+ return;
+
+ /*
+ * Check for flag range limits only. If flag == 1 then
+ * no additional timing information provided.
+ * Default GTF, GTF Secondary curve and CVT are not
+ * supported
+ */
+ if (range->flags != EDID_RANGE_LIMITS_ONLY_FLAG)
+ return;
+
+ adaptive_sync->min_vfreq = range->min_vfreq;
+ adaptive_sync->max_vfreq = range->max_vfreq;
+}
+
+static
+void drm_get_adaptive_sync_range(struct drm_connector *connector,
+ const struct edid *edid)
+{
+ struct drm_display_info *info = &connector->display_info;
+
+ if (!version_greater(edid, 1, 1))
+ return;
+
+ drm_for_each_detailed_block((u8 *)edid, get_adaptive_sync_range,
+ &info->adaptive_sync);
+
+ DRM_DEBUG_KMS("Adaptive Sync refresh rate range is %d Hz - %d Hz\n",
+ info->adaptive_sync.min_vfreq,
+ info->adaptive_sync.max_vfreq);
+}
+
/* A connector has no EDID information, so we've got no EDID to compute quirks from. Reset
* all of the values which would have been set from EDID
*/
@@ -4960,6 +5001,7 @@ drm_reset_display_info(struct drm_connector *connector)
memset(&info->hdmi, 0, sizeof(info->hdmi));

info->non_desktop = 0;
+ memset(&info->adaptive_sync, 0, sizeof(info->adaptive_sync));
}

u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edid)
@@ -4975,6 +5017,8 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi

info->non_desktop = !!(quirks & EDID_QUIRK_NON_DESKTOP);

+ drm_get_adaptive_sync_range(connector, edid);
+
DRM_DEBUG_KMS("non_desktop set to %d\n", info->non_desktop);

if (edid->revision < 3)
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 0df7a95ca5d9..2b22c0fa42c4 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -254,6 +254,23 @@ enum drm_panel_orientation {
DRM_MODE_PANEL_ORIENTATION_RIGHT_UP,
};

+/**
+ * struct drm_adaptive_sync_info - Panel's Adaptive Sync capabilities for
+ * &drm_display_info
+ *
+ * This struct is used to store a Panel's Adaptive Sync capabilities
+ * as parsed from EDID's detailed monitor range descriptor block.
+ *
+ * @min_vfreq: This is the min supported refresh rate in Hz from
+ * EDID's detailed monitor range.
+ * @max_vfreq: This is the max supported refresh rate in Hz from
+ * EDID's detailed monitor range
+ */
+struct drm_adaptive_sync_info {
+ u8 min_vfreq;
+ u8 max_vfreq;
+};
+
/*
* This is a consolidated colorimetry list supported by HDMI and
* DP protocol standard. The respective connectors will register
@@ -473,6 +490,11 @@ struct drm_display_info {
* @non_desktop: Non desktop display (HMD).
*/
bool non_desktop;
+
+ /**
+ * @adaptive_sync: Adaptive Sync capabilities of the DP/eDP sink
+ */
+ struct drm_adaptive_sync_info adaptive_sync;
};

int drm_display_info_set_bus_formats(struct drm_display_info *info,
--
2.19.1