drm/nouveau: No need to lock/unlock the VGA CRTC regs all the time.

Locking only makes sense in the VBIOS parsing code as it's executed
before CRTC init.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -6607,7 +6607,6 @@ static bool
 nouveau_bios_posted(struct drm_device *dev)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
-	bool was_locked;
 	unsigned htotal;
 
 	if (dev_priv->chipset >= NV_50) {
@@ -6617,13 +6616,14 @@ nouveau_bios_posted(struct drm_device *dev)
 		return true;
 	}
 
-	was_locked = NVLockVgaCrtcs(dev, false);
+	NVLockVgaCrtcs(dev, false);
 	htotal  = NVReadVgaCrtc(dev, 0, 0x06);
 	htotal |= (NVReadVgaCrtc(dev, 0, 0x07) & 0x01) << 8;
 	htotal |= (NVReadVgaCrtc(dev, 0, 0x07) & 0x20) << 4;
 	htotal |= (NVReadVgaCrtc(dev, 0, 0x25) & 0x01) << 10;
 	htotal |= (NVReadVgaCrtc(dev, 0, 0x41) & 0x01) << 11;
-	NVLockVgaCrtcs(dev, was_locked);
+	NVLockVgaCrtcs(dev, true);
+
 	return (htotal != 0);
 }
 
@@ -6632,7 +6632,6 @@ nouveau_bios_init(struct drm_device *dev)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	struct nvbios *bios = &dev_priv->vbios;
-	bool was_locked;
 	int ret;
 
 	if (!NVInitVBIOS(dev))
@@ -6667,14 +6666,14 @@ nouveau_bios_init(struct drm_device *dev)
 		return ret;
 
 	/* feature_byte on BMP is poor, but init always sets CR4B */
-	was_locked = NVLockVgaCrtcs(dev, false);
+	NVLockVgaCrtcs(dev, false);
 	if (bios->major_version < 5)
 		bios->is_mobile = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_4B) & 0x40;
 
 	/* all BIT systems need p_f_m_t for digital_min_front_porch */
 	if (bios->is_mobile || bios->major_version >= 5)
 		ret = parse_fp_mode_table(dev, bios);
-	NVLockVgaCrtcs(dev, was_locked);
+	NVLockVgaCrtcs(dev, true);
 
 	/* allow subsequent scripts to execute */
 	bios->execute = true;

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -102,44 +102,12 @@ nouveau_connector_destroy(struct drm_connector *drm_connector)
 	kfree(drm_connector);
 }
 
-static void
-nouveau_connector_ddc_prepare(struct drm_connector *connector, int *flags)
-{
-	struct drm_nouveau_private *dev_priv = connector->dev->dev_private;
-
-	if (dev_priv->card_type >= NV_50)
-		return;
-
-	*flags = 0;
-	if (NVLockVgaCrtcs(dev_priv->dev, false))
-		*flags |= 1;
-	if (nv_heads_tied(dev_priv->dev))
-		*flags |= 2;
-
-	if (*flags & 2)
-		NVSetOwner(dev_priv->dev, 0); /* necessary? */
-}
-
-static void
-nouveau_connector_ddc_finish(struct drm_connector *connector, int flags)
-{
-	struct drm_nouveau_private *dev_priv = connector->dev->dev_private;
-
-	if (dev_priv->card_type >= NV_50)
-		return;
-
-	if (flags & 2)
-		NVSetOwner(dev_priv->dev, 4);
-	if (flags & 1)
-		NVLockVgaCrtcs(dev_priv->dev, true);
-}
-
 static struct nouveau_i2c_chan *
 nouveau_connector_ddc_detect(struct drm_connector *connector,
 			     struct nouveau_encoder **pnv_encoder)
 {
 	struct drm_device *dev = connector->dev;
-	int ret, flags, i;
+	int i;
 
 	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
 		struct nouveau_i2c_chan *i2c;
@@ -155,17 +123,9 @@ nouveau_connector_ddc_detect(struct drm_connector *connector,
 		if (!obj)
 			continue;
 		nv_encoder = nouveau_encoder(obj_to_encoder(obj));
+		i2c = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
 
-		if (nv_encoder->dcb->i2c_index < 0xf)
-			i2c = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
-		if (!i2c)
-			continue;
-
-		nouveau_connector_ddc_prepare(connector, &flags);
-		ret = nouveau_probe_i2c_addr(i2c, 0x50);
-		nouveau_connector_ddc_finish(connector, flags);
-
-		if (ret) {
+		if (i2c && nouveau_probe_i2c_addr(i2c, 0x50)) {
 			*pnv_encoder = nv_encoder;
 			return i2c;
 		}
@@ -218,7 +178,7 @@ nouveau_connector_detect(struct drm_connector *connector)
 	struct nouveau_connector *nv_connector = nouveau_connector(connector);
 	struct nouveau_encoder *nv_encoder = NULL;
 	struct nouveau_i2c_chan *i2c;
-	int type, flags;
+	int type;
 
 	/* Cleanup the previous EDID block. */
 	if (nv_connector->edid) {
@@ -229,9 +189,7 @@ nouveau_connector_detect(struct drm_connector *connector)
 
 	i2c = nouveau_connector_ddc_detect(connector, &nv_encoder);
 	if (i2c) {
-		nouveau_connector_ddc_prepare(connector, &flags);
 		nv_connector->edid = drm_get_edid(connector, &i2c->adapter);
-		nouveau_connector_ddc_finish(connector, flags);
 		drm_mode_connector_update_edid_property(connector,
 							nv_connector->edid);
 		if (!nv_connector->edid) {

drivers/gpu/drm/nouveau/nouveau_drv.c

@@ -321,10 +321,9 @@ nouveau_pci_resume(struct pci_dev *pdev)
 			NV_ERROR(dev, "Could not pin/map cursor.\n");
 	}
 
-	if (dev_priv->card_type < NV_50) {
+	if (dev_priv->card_type < NV_50)
 		nv04_display_restore(dev);
-		NVLockVgaCrtcs(dev, false);
-	} else
+	else
 		nv50_display_init(dev);
 
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {

drivers/gpu/drm/nouveau/nv04_display.c

@@ -32,8 +32,6 @@
 #include "nouveau_encoder.h"
 #include "nouveau_connector.h"
 
-#define MULTIPLE_ENCODERS(e) (e & (e - 1))
-
 static void
 nv04_display_store_initial_head_owner(struct drm_device *dev)
 {
@@ -41,7 +39,7 @@ nv04_display_store_initial_head_owner(struct drm_device *dev)
 
 	if (dev_priv->chipset != 0x11) {
 		dev_priv->crtc_owner = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_44);
-		goto ownerknown;
+		return;
 	}
 
 	/* reading CR44 is broken on nv11, so we attempt to infer it */
@@ -52,8 +50,6 @@ nv04_display_store_initial_head_owner(struct drm_device *dev)
 		bool tvA = false;
 		bool tvB = false;
 
-		NVLockVgaCrtcs(dev, false);
-
 		slaved_on_B = NVReadVgaCrtc(dev, 1, NV_CIO_CRE_PIXEL_INDEX) &
 									0x80;
 		if (slaved_on_B)
@@ -66,8 +62,6 @@ nv04_display_store_initial_head_owner(struct drm_device *dev)
 			tvA = !(NVReadVgaCrtc(dev, 0, NV_CIO_CRE_LCD__INDEX) &
 					MASK(NV_CIO_CRE_LCD_LCD_SELECT));
 
-		NVLockVgaCrtcs(dev, true);
-
 		if (slaved_on_A && !tvA)
 			dev_priv->crtc_owner = 0x0;
 		else if (slaved_on_B && !tvB)
@@ -79,12 +73,6 @@ nv04_display_store_initial_head_owner(struct drm_device *dev)
 		else
 			dev_priv->crtc_owner = 0x0;
 	}
-
-ownerknown:
-	/* we need to ensure the heads are not tied henceforth, or reading any
-	 * 8 bit reg on head B will fail
-	 * setting a single arbitrary head solves that */
-	NVSetOwner(dev, 0);
 }
 
 int
@@ -99,8 +87,13 @@ nv04_display_create(struct drm_device *dev)
 
 	NV_DEBUG_KMS(dev, "\n");
 
-	if (nv_two_heads(dev))
+	NVLockVgaCrtcs(dev, false);
+
+	if (nv_two_heads(dev)) {
 		nv04_display_store_initial_head_owner(dev);
+		NVSetOwner(dev, 0);
+	}
+
 	nouveau_hw_save_vga_fonts(dev, 1);
 
 	drm_mode_config_init(dev);
@@ -168,8 +161,6 @@ nv04_display_create(struct drm_device *dev)
 	}
 
 	/* Save previous state */
-	NVLockVgaCrtcs(dev, false);
-
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
 		crtc->funcs->save(crtc);
 
@@ -185,6 +176,7 @@ nv04_display_create(struct drm_device *dev)
 void
 nv04_display_destroy(struct drm_device *dev)
 {
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	struct drm_encoder *encoder;
 	struct drm_crtc *crtc;
 
@@ -200,8 +192,6 @@ nv04_display_destroy(struct drm_device *dev)
 	}
 
 	/* Restore state */
-	NVLockVgaCrtcs(dev, false);
-
 	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 		struct drm_encoder_helper_funcs *func = encoder->helper_private;
 
@@ -214,12 +204,15 @@ nv04_display_destroy(struct drm_device *dev)
 	drm_mode_config_cleanup(dev);
 
 	nouveau_hw_save_vga_fonts(dev, 0);
+
+	if (nv_two_heads(dev))
+		NVSetOwner(dev, dev_priv->crtc_owner);
+	NVLockVgaCrtcs(dev, true);
 }
 
 void
 nv04_display_restore(struct drm_device *dev)
 {
-	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	struct drm_encoder *encoder;
 	struct drm_crtc *crtc;
 
@@ -241,10 +234,5 @@ nv04_display_restore(struct drm_device *dev)
 
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
 		crtc->funcs->restore(crtc);
-
-	if (nv_two_heads(dev))
-		NVSetOwner(dev, dev_priv->crtc_owner);
-
-	NVLockVgaCrtcs(dev, true);
 }
 

drivers/gpu/drm/nouveau/nv04_tv.c

@@ -194,7 +194,6 @@ nv04_tv_create(struct drm_connector *connector, struct dcb_entry *entry)
 	struct nouveau_i2c_chan *i2c =
 		nouveau_i2c_find(dev, entry->i2c_index);
 	int type, ret;
-	bool was_locked;
 
 	/* Ensure that we can talk to this encoder */
 	type = nv04_tv_identify(dev, entry->i2c_index);
@@ -224,13 +223,8 @@ nv04_tv_create(struct drm_connector *connector, struct dcb_entry *entry)
 	nv_encoder->or = ffs(entry->or) - 1;
 
 	/* Run the slave-specific initialization */
-	was_locked = NVLockVgaCrtcs(dev, false);
-
 	ret = drm_i2c_encoder_init(dev, to_encoder_slave(encoder),
 				   &i2c->adapter, &nv04_tv_encoder_info[type]);
-
-	NVLockVgaCrtcs(dev, was_locked);
-
 	if (ret < 0)
 		goto fail_cleanup;