[PATCH v3 2/3] drm/amd/display: Add freesync video modes based on preferred modes

From: Aurabindo Pillai <aurabindo.pillai@amd.com>
To: <amd-gfx@lists.freedesktop.org>,
	<dri-devel@lists.freedesktop.org>, <nicholas.kazlauskas@amd.com>
Cc: stylon.wang@amd.com, thong.thai@amd.com, shashank.sharma@amd.com,
	aurabindo.pillai@amd.com, wayne.lin@amd.com,
	alexander.deucher@amd.com,
	"Christian König" <christian.koenig@amd.com>
Subject: [PATCH v3 2/3] drm/amd/display: Add freesync video modes based on preferred modes
Date: Mon, 4 Jan 2021 16:07:59 -0500	[thread overview]
Message-ID: <20210104210800.789944-3-aurabindo.pillai@amd.com> (raw)
In-Reply-To: <20210104210800.789944-1-aurabindo.pillai@amd.com>

[Why&How]
If experimental freesync video mode module parameter is enabled, add
few extra display modes into the driver's mode list corresponding to common
video frame rates. When userspace sets these modes, no modeset will be
performed (if current mode was one of freesync modes or the base freesync mode
based off which timings have been generated for the rest of the freesync modes)
since these modes only differ from the base mode with front porch timing.

Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Shashank Sharma <shashank.sharma@amd.com>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 170 ++++++++++++++++++
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |   2 +
 2 files changed, 172 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 245bd1284e5f..aaef2fb528fd 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5174,6 +5174,59 @@ static void dm_enable_per_frame_crtc_master_sync(struct dc_state *context)
 	set_master_stream(context->streams, context->stream_count);
 }
 
+static struct drm_display_mode *
+get_highest_refresh_rate_mode(struct amdgpu_dm_connector *aconnector,
+			  bool use_probed_modes)
+{
+	struct drm_display_mode *m, *m_pref = NULL;
+	u16 current_refresh, highest_refresh;
+	struct list_head *list_head = use_probed_modes ?
+						    &aconnector->base.probed_modes :
+						    &aconnector->base.modes;
+
+	if (aconnector->freesync_vid_base.clock != 0)
+		return &aconnector->freesync_vid_base;
+
+	/* Find the preferred mode */
+	list_for_each_entry (m, list_head, head) {
+		if (m->type & DRM_MODE_TYPE_PREFERRED) {
+			m_pref = m;
+			break;
+		}
+	}
+
+	if (!m_pref) {
+		/* Probably an EDID with no preferred mode. Fallback to first entry */
+		m_pref = list_first_entry_or_null(
+			&aconnector->base.modes, struct drm_display_mode, head);
+		if (!m_pref) {
+			DRM_DEBUG_DRIVER("No preferred mode found in EDID\n");
+			return NULL;
+		}
+	}
+
+	highest_refresh = drm_mode_vrefresh(m_pref);
+
+	/*
+	 * Find the mode with highest refresh rate with same resolution.
+	 * For some monitors, preferred mode is not the mode with highest
+	 * supported refresh rate.
+	 */
+	list_for_each_entry (m, list_head, head) {
+		current_refresh  = drm_mode_vrefresh(m);
+
+		if (m->hdisplay == m_pref->hdisplay &&
+		    m->vdisplay == m_pref->vdisplay &&
+		    highest_refresh < current_refresh) {
+			highest_refresh = current_refresh;
+			m_pref = m;
+		}
+	}
+
+	aconnector->freesync_vid_base = *m_pref;
+	return m_pref;
+}
+
 static struct dc_stream_state *
 create_stream_for_sink(struct amdgpu_dm_connector *aconnector,
 		       const struct drm_display_mode *drm_mode,
@@ -6999,6 +7052,122 @@ static void amdgpu_dm_connector_ddc_get_modes(struct drm_connector *connector,
 	}
 }
 
+static bool is_duplicate_mode(struct amdgpu_dm_connector *aconnector,
+			      struct drm_display_mode *mode)
+{
+	struct drm_display_mode *m;
+
+	list_for_each_entry (m, &aconnector->base.probed_modes, head) {
+		if (drm_mode_equal(m, mode))
+			return true;
+	}
+
+	return false;
+}
+
+static uint add_fs_modes(struct amdgpu_dm_connector *aconnector,
+			 struct detailed_data_monitor_range *range)
+{
+	const struct drm_display_mode *m;
+	struct drm_display_mode *new_mode;
+	uint i;
+	uint32_t new_modes_count = 0;
+
+	/* Standard FPS values
+	 *
+	 * 23.976   - TV/NTSC
+	 * 24 	    - Cinema
+	 * 25 	    - TV/PAL
+	 * 29.97    - TV/NTSC
+	 * 30 	    - TV/NTSC
+	 * 48 	    - Cinema HFR
+	 * 50 	    - TV/PAL
+	 * 60 	    - Commonly used
+	 * 48,72,96 - Multiples of 24
+	 */
+	const uint32_t common_rates[] = { 23976, 24000, 25000, 29970, 30000,
+					 48000, 50000, 60000, 72000, 96000 };
+
+	/*
+	 * Find mode with highest refresh rate with the same resolution
+	 * as the preferred mode. Some monitors report a preferred mode
+	 * with lower resolution than the highest refresh rate supported.
+	 */
+
+	m = get_highest_refresh_rate_mode(aconnector, true);
+	if (!m)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(common_rates); i++) {
+		uint64_t target_vtotal, target_vtotal_diff;
+		uint64_t num, den;
+
+		if (drm_mode_vrefresh(m) * 1000 < common_rates[i])
+			continue;
+
+		if (common_rates[i] < range->min_vfreq * 1000)
+			continue;
+
+		num = (unsigned long long)m->clock * 1000 * 1000;
+		den = common_rates[i] * (unsigned long long)m->htotal;
+		target_vtotal = div_u64(num, den);
+		target_vtotal_diff = target_vtotal - m->vtotal;
+
+		/* Check for illegal modes */
+		if (m->vsync_start + target_vtotal_diff < m->vdisplay ||
+		    m->vsync_end + target_vtotal_diff < m->vsync_start ||
+		    m->vtotal + target_vtotal_diff < m->vsync_end)
+			continue;
+
+		new_mode = drm_mode_duplicate(aconnector->base.dev, m);
+		if (!new_mode)
+			goto out;
+
+		new_mode->vtotal += (u16)target_vtotal_diff;
+		new_mode->vsync_start += (u16)target_vtotal_diff;
+		new_mode->vsync_end += (u16)target_vtotal_diff;
+		new_mode->type &= ~DRM_MODE_TYPE_PREFERRED;
+		new_mode->type |= DRM_MODE_TYPE_DRIVER;
+
+		if (!is_duplicate_mode(aconnector, new_mode)) {
+			drm_mode_probed_add(&aconnector->base, new_mode);
+			new_modes_count += 1;
+		} else
+			drm_mode_destroy(aconnector->base.dev, new_mode);
+	}
+ out:
+	return new_modes_count;
+}
+
+static void amdgpu_dm_connector_add_freesync_modes(struct drm_connector *connector,
+						   struct edid *edid)
+{
+	uint8_t i;
+	struct detailed_timing *timing;
+	struct detailed_non_pixel *data;
+	struct detailed_data_monitor_range *range;
+	struct amdgpu_dm_connector *amdgpu_dm_connector =
+		to_amdgpu_dm_connector(connector);
+
+	if (!(amdgpu_exp_freesync_vid_mode && edid))
+		return;
+
+	if (edid->version == 1 && edid->revision > 1) {
+		for (i = 0; i < 4; i++) {
+			timing = &edid->detailed_timings[i];
+			data = &timing->data.other_data;
+			range = &data->data.range;
+
+			/* Check if monitor has continuous frequency mode */
+			if (data->type == EDID_DETAIL_MONITOR_RANGE &&
+			    range->max_vfreq - range->min_vfreq > 10) {
+				amdgpu_dm_connector->num_modes += add_fs_modes(amdgpu_dm_connector, range);
+				break;
+			}
+		}
+	}
+}
+
 static int amdgpu_dm_connector_get_modes(struct drm_connector *connector)
 {
 	struct amdgpu_dm_connector *amdgpu_dm_connector =
@@ -7014,6 +7183,7 @@ static int amdgpu_dm_connector_get_modes(struct drm_connector *connector)
 	} else {
 		amdgpu_dm_connector_ddc_get_modes(connector, edid);
 		amdgpu_dm_connector_add_common_modes(encoder, connector);
+		amdgpu_dm_connector_add_freesync_modes(connector, edid);
 	}
 	amdgpu_dm_fbc_init(connector);
 
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index c9d82b9e4d7e..3ea85be9c546 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -432,6 +432,8 @@ struct amdgpu_dm_connector {
 #endif
 	bool force_yuv420_output;
 	struct dsc_preferred_settings dsc_settings;
+	/* Cached display modes */
+	struct drm_display_mode freesync_vid_base;
 };
 
 #define to_amdgpu_dm_connector(x) container_of(x, struct amdgpu_dm_connector, base)
-- 
2.30.0

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