diff mbox series

[v3,1/1] drm/mediatek: Adjust bandwidth limit for DP

Message ID 20250318140236.13650-2-liankun.yang@mediatek.com (mailing list archive)
State New
Headers show
Series *** SUBJECT HERE *** | expand

Commit Message

Liankun Yang March 18, 2025, 2:02 p.m. UTC
By adjusting the order of link training and relocating it to HPD,
link training can identify the usability of each lane in the current link.

It also supports handling signal instability and weakness due to
environmental issues, enabling the acquisition of a stable bandwidth
for the current link. Subsequently, DP work can proceed based on
the actual maximum bandwidth.

It should training in the hpd event thread.
Check the mode with lane count and link rate of training.

Signed-off-by: Liankun Yang <liankun.yang@mediatek.com>
---
Change in V3:
- Remove 'mtk_dp->enabled = false" in atomic disable.
- Remove 'mtk_dp->enabled = true" in atomic enable.
Per suggestion from the previous thread:
https://patchwork.kernel.org/project/linux-mediatek/patch/20241025083036.8829-4-liankun.yang@mediatek.com/

Change in V2:
- Adjust DP training timing.
- Adjust parse capabilities timing.
- Add power on/off for connect/disconnect.
Per suggestion from the previous thread:
https://patchwork.kernel.org/project/linux-mediatek/patch/20240315015233.2023-1-liankun.yang@mediatek.com/
---
 drivers/gpu/drm/mediatek/mtk_dp.c | 39 ++++++++++++++++---------------
 1 file changed, 20 insertions(+), 19 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
index 3d4648d2e15f..fb76fc1bf497 100644
--- a/drivers/gpu/drm/mediatek/mtk_dp.c
+++ b/drivers/gpu/drm/mediatek/mtk_dp.c
@@ -1976,6 +1976,7 @@  static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
 	struct mtk_dp *mtk_dp = dev;
 	unsigned long flags;
 	u32 status;
+	int ret;
 
 	if (mtk_dp->need_debounce && mtk_dp->train_info.cable_plugged_in)
 		msleep(100);
@@ -1994,9 +1995,28 @@  static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
 			memset(&mtk_dp->info.audio_cur_cfg, 0,
 			       sizeof(mtk_dp->info.audio_cur_cfg));
 
+			mtk_dp->enabled = false;
+			/* power off aux */
+			mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
+			       DP_PWR_STATE_BANDGAP_TPLL,
+			       DP_PWR_STATE_MASK);
+
 			mtk_dp->need_debounce = false;
 			mod_timer(&mtk_dp->debounce_timer,
 				  jiffies + msecs_to_jiffies(100) - 1);
+		} else {
+			mtk_dp_aux_panel_poweron(mtk_dp, true);
+
+			ret = mtk_dp_parse_capabilities(mtk_dp);
+			if (ret)
+				drm_err(mtk_dp->drm_dev, "Can't parse capabilities\n");
+
+			/* Training */
+			ret = mtk_dp_training(mtk_dp);
+			if (ret)
+				drm_err(mtk_dp->drm_dev, "Training failed, %d\n", ret);
+
+			mtk_dp->enabled = true;
 		}
 	}
 
@@ -2162,16 +2182,6 @@  static const struct drm_edid *mtk_dp_edid_read(struct drm_bridge *bridge,
 
 	drm_edid = drm_edid_read_ddc(connector, &mtk_dp->aux.ddc);
 
-	/*
-	 * Parse capability here to let atomic_get_input_bus_fmts and
-	 * mode_valid use the capability to calculate sink bitrates.
-	 */
-	if (mtk_dp_parse_capabilities(mtk_dp)) {
-		drm_err(mtk_dp->drm_dev, "Can't parse capabilities\n");
-		drm_edid_free(drm_edid);
-		drm_edid = NULL;
-	}
-
 	if (drm_edid) {
 		/*
 		 * FIXME: get rid of drm_edid_raw()
@@ -2365,13 +2375,6 @@  static void mtk_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 
 	mtk_dp_aux_panel_poweron(mtk_dp, true);
 
-	/* Training */
-	ret = mtk_dp_training(mtk_dp);
-	if (ret) {
-		drm_err(mtk_dp->drm_dev, "Training failed, %d\n", ret);
-		goto power_off_aux;
-	}
-
 	ret = mtk_dp_video_config(mtk_dp);
 	if (ret)
 		goto power_off_aux;
@@ -2389,7 +2392,6 @@  static void mtk_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 		       sizeof(mtk_dp->info.audio_cur_cfg));
 	}
 
-	mtk_dp->enabled = true;
 	mtk_dp_update_plugged_status(mtk_dp);
 
 	return;
@@ -2404,7 +2406,6 @@  static void mtk_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 {
 	struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
 
-	mtk_dp->enabled = false;
 	mtk_dp_update_plugged_status(mtk_dp);
 	mtk_dp_video_enable(mtk_dp, false);
 	mtk_dp_audio_mute(mtk_dp, true);