From: Ben Skeggs <bskeggs@redhat.com>
Date: Tue, 4 Sep 2018 15:57:07 +1000
Subject: drm/nouveau/disp: move eDP panel power handling
Git-commit: f6d52b2172b1adfde010df34730290c282ee641b
Patch-mainline: v4.19-rc4
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

We need to do this earlier to prevent aux channel timeouts in resume
paths on certain systems.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/nouveau/nouveau_connector.c   |   23 ----------------
 drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c |   37 +++++++++++++++++++++++---
 2 files changed, 35 insertions(+), 25 deletions(-)

--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -409,26 +409,11 @@ static struct nouveau_encoder *
 nouveau_connector_ddc_detect(struct drm_connector *connector)
 {
 	struct drm_device *dev = connector->dev;
-	struct nouveau_connector *nv_connector = nouveau_connector(connector);
-	struct nouveau_drm *drm = nouveau_drm(dev);
-	struct nvkm_gpio *gpio = nvxx_gpio(&drm->client.device);
 	struct nouveau_encoder *nv_encoder = NULL, *found = NULL;
 	struct drm_encoder *encoder;
-	int i, ret, panel = -ENODEV;
+	int i, ret;
 	bool switcheroo_ddc = false;
 
-	/* eDP panels need powering on by us (if the VBIOS doesn't default it
-	 * to on) before doing any AUX channel transactions.  LVDS panel power
-	 * is handled by the SOR itself, and not required for LVDS DDC.
-	 */
-	if (nv_connector->type == DCB_CONNECTOR_eDP) {
-		panel = nvkm_gpio_get(gpio, 0, DCB_GPIO_PANEL_POWER, 0xff);
-		if (panel == 0) {
-			nvkm_gpio_set(gpio, 0, DCB_GPIO_PANEL_POWER, 0xff, 1);
-			msleep(300);
-		}
-	}
-
 	drm_connector_for_each_possible_encoder(connector, encoder, i) {
 		nv_encoder = nouveau_encoder(encoder);
 
@@ -462,12 +447,6 @@ nouveau_connector_ddc_detect(struct drm_
 			break;
 	}
 
-	/* eDP panel not detected, restore panel power GPIO to previous
-	 * state to avoid confusing the SOR for other output types.
-	 */
-	if (!found && panel == 0)
-		nvkm_gpio_set(gpio, 0, DCB_GPIO_PANEL_POWER, 0xff, panel);
-
 	return found;
 }
 
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
@@ -28,6 +28,7 @@
 
 #include <subdev/bios.h>
 #include <subdev/bios/init.h>
+#include <subdev/gpio.h>
 #include <subdev/i2c.h>
 
 #include <nvif/event.h>
@@ -491,7 +492,7 @@ done:
 	return ret;
 }
 
-static void
+static bool
 nvkm_dp_enable(struct nvkm_dp *dp, bool enable)
 {
 	struct nvkm_i2c_aux *aux = dp->aux;
@@ -505,7 +506,7 @@ nvkm_dp_enable(struct nvkm_dp *dp, bool
 
 		if (!nvkm_rdaux(aux, DPCD_RC00_DPCD_REV, dp->dpcd,
 				sizeof(dp->dpcd)))
-			return;
+			return true;
 	}
 
 	if (dp->present) {
@@ -515,6 +516,7 @@ nvkm_dp_enable(struct nvkm_dp *dp, bool
 	}
 
 	atomic_set(&dp->lt.done, 0);
+	return false;
 }
 
 static int
@@ -555,9 +557,38 @@ nvkm_dp_fini(struct nvkm_outp *outp)
 static void
 nvkm_dp_init(struct nvkm_outp *outp)
 {
+	struct nvkm_gpio *gpio = outp->disp->engine.subdev.device->gpio;
 	struct nvkm_dp *dp = nvkm_dp(outp);
+
 	nvkm_notify_put(&dp->outp.conn->hpd);
-	nvkm_dp_enable(dp, true);
+
+	/* eDP panels need powering on by us (if the VBIOS doesn't default it
+	 * to on) before doing any AUX channel transactions.  LVDS panel power
+	 * is handled by the SOR itself, and not required for LVDS DDC.
+	 */
+	if (dp->outp.conn->info.type == DCB_CONNECTOR_eDP) {
+		int power = nvkm_gpio_get(gpio, 0, DCB_GPIO_PANEL_POWER, 0xff);
+		if (power == 0)
+			nvkm_gpio_set(gpio, 0, DCB_GPIO_PANEL_POWER, 0xff, 1);
+
+		/* We delay here unconditionally, even if already powered,
+		 * because some laptop panels having a significant resume
+		 * delay before the panel begins responding.
+		 *
+		 * This is likely a bit of a hack, but no better idea for
+		 * handling this at the moment.
+		 */
+		msleep(300);
+
+		/* If the eDP panel can't be detected, we need to restore
+		 * the panel power GPIO to avoid breaking another output.
+		 */
+		if (!nvkm_dp_enable(dp, true) && power == 0)
+			nvkm_gpio_set(gpio, 0, DCB_GPIO_PANEL_POWER, 0xff, 0);
+	} else {
+		nvkm_dp_enable(dp, true);
+	}
+
 	nvkm_notify_get(&dp->hpd);
 }