[PATCH 1/4] drm/nouveau: dispnv50: Don't create MSTMs for eDP connectors

[PATCH 1/4] drm/nouveau: dispnv50: Don't create MSTMs for eDP connectors

[Lyude Paul]

On the ThinkPad P71, we have one eDP connector exposed along with 5 DP
connectors, resulting in a total of 11 TMDS encoders. Since the GPU on
this system is also capable of MST, we create an additional 4 fake MST
encoders for each DP port. Unfortunately, we also do this for the eDP
port as well, resulting in:

  1 eDP port: +1 TMDS encoder
              +4 DPMST encoders
  5 DP ports: +2 TMDS encoders
              +4 DPMST encoders
	      *5 ports
	      == 35 encoders

Which breaks things, since DRM has a hard coded limit of 32 encoders.
So, fix this by not creating MSTMs for any eDP connectors. This brings
us down to 31 encoders, although we can do better.

This fixes driver probing for nouveau on the ThinkPad P71.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 307584107d77..b46be8a091e9 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1603,7 +1603,8 @@ nv50_sor_create(struct drm_connector *connector, struct dcb_output *dcbe)
 			nv_encoder->aux = aux;
 		}
 
-		if ((data = nvbios_dp_table(bios, &ver, &hdr, &cnt, &len)) &&
+		if (nv_connector->type != DCB_CONNECTOR_eDP &&
+		    (data = nvbios_dp_table(bios, &ver, &hdr, &cnt, &len)) &&
 		    ver >= 0x40 && (nvbios_rd08(bios, data + 0x08) & 0x04)) {
 			ret = nv50_mstm_new(nv_encoder, &nv_connector->aux, 16,
 					    nv_connector->base.base.id,
-- 
2.21.0

[PATCH 2/4] drm/nouveau: dispnv50: Remove nv50_mstc_best_encoder()

[Lyude Paul]

When drm_connector_helper_funcs->atomic_best_encoder is defined,
->best_encoder is ignored both by the atomic modesetting helpers. That
being said, this hook is completely broken anyway - it always returns
the first msto for a given mstc, despite the fact it might already be in
use.

So, just get rid of it. We'll need this in a moment anyway, when we make
mstos per-head as opposed to per-connector.

Signed-off-by: Lyude Paul <lyude@redhat.com>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index b46be8a091e9..a3f350fdfa8c 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -920,14 +920,6 @@ nv50_mstc_atomic_best_encoder(struct drm_connector *connector,
 	return &mstc->mstm->msto[head->base.index]->encoder;
 }
 
-static struct drm_encoder *
-nv50_mstc_best_encoder(struct drm_connector *connector)
-{
-	struct nv50_mstc *mstc = nv50_mstc(connector);
-
-	return &mstc->mstm->msto[0]->encoder;
-}
-
 static enum drm_mode_status
 nv50_mstc_mode_valid(struct drm_connector *connector,
 		     struct drm_display_mode *mode)
@@ -990,7 +982,6 @@ static const struct drm_connector_helper_funcs
 nv50_mstc_help = {
 	.get_modes = nv50_mstc_get_modes,
 	.mode_valid = nv50_mstc_mode_valid,
-	.best_encoder = nv50_mstc_best_encoder,
 	.atomic_best_encoder = nv50_mstc_atomic_best_encoder,
 	.atomic_check = nv50_mstc_atomic_check,
 };
-- 
2.21.0

[PATCH 3/4] drm/nouveau: dispnv50: Use less encoders by making mstos per-head

[Lyude Paul]

Currently, for every single MST capable DRM connector we create a set of
fake encoders, one for each possible head. Unfortunately this ends up
being a huge waste of encoders. While this currently isn't causing us
any problems, it's extremely close to doing so.

The ThinkPad P71 is a good example of this. Originally when trying to
figure out why nouveau was failing to load on this laptop, I discovered
it was because nouveau was creating too many encoders. This ended up
being because we were mistakenly creating MST encoders for the eDP port,
however we are still extremely close to hitting the encoder limit on
this machine as it exposes 1 eDP port and 5 DP ports, resulting in 31
encoders.

So while this fix didn't end up being necessary to fix the P71, we still
need to implement this so that we avoid hitting the encoder limit for
valid display configurations in the event that some machine with more
connectors then this becomes available. Plus, we don't want to let good
code go to waste :)

So, use less encoders by only creating one MSTO per head. Then, attach
each new MSTC to each MSTO which corresponds to a head that it's parent
DP port is capable of using. This brings the number of encoders we
register on the ThinkPad P71 from 31, down to just 15. Yay!

Signed-off-by: Lyude Paul <lyude@redhat.com>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 92 +++++++++++++++----------
 drivers/gpu/drm/nouveau/dispnv50/disp.h |  2 +
 drivers/gpu/drm/nouveau/dispnv50/head.c | 17 +++--
 drivers/gpu/drm/nouveau/dispnv50/head.h |  3 +-
 4 files changed, 68 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index a3f350fdfa8c..d23ac13763b5 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -650,7 +650,6 @@ struct nv50_mstm {
 	struct nouveau_encoder *outp;
 
 	struct drm_dp_mst_topology_mgr mgr;
-	struct nv50_msto *msto[4];
 
 	bool modified;
 	bool disabled;
@@ -716,7 +715,6 @@ nv50_msto_cleanup(struct nv50_msto *msto)
 	drm_dp_mst_deallocate_vcpi(&mstm->mgr, mstc->port);
 
 	msto->mstc = NULL;
-	msto->head = NULL;
 	msto->disabled = false;
 }
 
@@ -846,7 +844,6 @@ nv50_msto_enable(struct drm_encoder *encoder)
 
 	mstm->outp->update(mstm->outp, head->base.index, armh, proto, depth);
 
-	msto->head = head;
 	msto->mstc = mstc;
 	mstm->modified = true;
 }
@@ -887,37 +884,40 @@ nv50_msto = {
 	.destroy = nv50_msto_destroy,
 };
 
-static int
-nv50_msto_new(struct drm_device *dev, u32 heads, const char *name, int id,
-	      struct nv50_msto **pmsto)
+static struct nv50_msto *
+nv50_msto_new(struct drm_device *dev, struct nv50_head *head, int id)
 {
 	struct nv50_msto *msto;
 	int ret;
 
-	if (!(msto = *pmsto = kzalloc(sizeof(*msto), GFP_KERNEL)))
-		return -ENOMEM;
+	msto = kzalloc(sizeof(*msto), GFP_KERNEL);
+	if (!msto)
+		return ERR_PTR(-ENOMEM);
 
 	ret = drm_encoder_init(dev, &msto->encoder, &nv50_msto,
-			       DRM_MODE_ENCODER_DPMST, "%s-mst-%d", name, id);
+			       DRM_MODE_ENCODER_DPMST, "mst-%d", id);
 	if (ret) {
-		kfree(*pmsto);
-		*pmsto = NULL;
-		return ret;
+		kfree(msto);
+		return ERR_PTR(ret);
 	}
 
 	drm_encoder_helper_add(&msto->encoder, &nv50_msto_help);
-	msto->encoder.possible_crtcs = heads;
-	return 0;
+	msto->encoder.possible_crtcs = drm_crtc_mask(&head->base.base);
+	msto->head = head;
+	return msto;
 }
 
 static struct drm_encoder *
 nv50_mstc_atomic_best_encoder(struct drm_connector *connector,
 			      struct drm_connector_state *connector_state)
 {
-	struct nv50_head *head = nv50_head(connector_state->crtc);
 	struct nv50_mstc *mstc = nv50_mstc(connector);
+	struct drm_crtc *crtc = connector_state->crtc;
 
-	return &mstc->mstm->msto[head->base.index]->encoder;
+	if (!(mstc->mstm->outp->dcb->heads & drm_crtc_mask(crtc)))
+		return NULL;
+
+	return &nv50_head(crtc)->msto->encoder;
 }
 
 static enum drm_mode_status
@@ -1036,8 +1036,9 @@ nv50_mstc_new(struct nv50_mstm *mstm, struct drm_dp_mst_port *port,
 	      const char *path, struct nv50_mstc **pmstc)
 {
 	struct drm_device *dev = mstm->outp->base.base.dev;
+	struct drm_crtc *crtc;
 	struct nv50_mstc *mstc;
-	int ret, i;
+	int ret;
 
 	if (!(mstc = *pmstc = kzalloc(sizeof(*mstc), GFP_KERNEL)))
 		return -ENOMEM;
@@ -1057,8 +1058,13 @@ nv50_mstc_new(struct nv50_mstm *mstm, struct drm_dp_mst_port *port,
 	mstc->connector.funcs->reset(&mstc->connector);
 	nouveau_conn_attach_properties(&mstc->connector);
 
-	for (i = 0; i < ARRAY_SIZE(mstm->msto) && mstm->msto[i]; i++)
-		drm_connector_attach_encoder(&mstc->connector, &mstm->msto[i]->encoder);
+	drm_for_each_crtc(crtc, dev) {
+		if (!(mstm->outp->dcb->heads & drm_crtc_mask(crtc)))
+			continue;
+
+		drm_connector_attach_encoder(&mstc->connector,
+					     &nv50_head(crtc)->msto->encoder);
+	}
 
 	drm_object_attach_property(&mstc->connector.base, dev->mode_config.path_property, 0);
 	drm_object_attach_property(&mstc->connector.base, dev->mode_config.tile_property, 0);
@@ -1332,7 +1338,7 @@ nv50_mstm_new(struct nouveau_encoder *outp, struct drm_dp_aux *aux, int aux_max,
 	const int max_payloads = hweight8(outp->dcb->heads);
 	struct drm_device *dev = outp->base.base.dev;
 	struct nv50_mstm *mstm;
-	int ret, i;
+	int ret;
 	u8 dpcd;
 
 	/* This is a workaround for some monitors not functioning
@@ -1355,13 +1361,6 @@ nv50_mstm_new(struct nouveau_encoder *outp, struct drm_dp_aux *aux, int aux_max,
 	if (ret)
 		return ret;
 
-	for (i = 0; i < max_payloads; i++) {
-		ret = nv50_msto_new(dev, outp->dcb->heads, outp->base.base.name,
-				    i, &mstm->msto[i]);
-		if (ret)
-			return ret;
-	}
-
 	return 0;
 }
 
@@ -1540,17 +1539,24 @@ nv50_sor_func = {
 	.destroy = nv50_sor_destroy,
 };
 
+static bool nv50_has_mst(struct nouveau_drm *drm)
+{
+	struct nvkm_bios *bios = nvxx_bios(&drm->client.device);
+	u32 data;
+	u8 ver, hdr, cnt, len;
+
+	data = nvbios_dp_table(bios, &ver, &hdr, &cnt, &len);
+	return data && ver >= 0x40 && (nvbios_rd08(bios, data + 0x08) & 0x04);
+}
+
 static int
 nv50_sor_create(struct drm_connector *connector, struct dcb_output *dcbe)
 {
 	struct nouveau_connector *nv_connector = nouveau_connector(connector);
 	struct nouveau_drm *drm = nouveau_drm(connector->dev);
-	struct nvkm_bios *bios = nvxx_bios(&drm->client.device);
 	struct nvkm_i2c *i2c = nvxx_i2c(&drm->client.device);
 	struct nouveau_encoder *nv_encoder;
 	struct drm_encoder *encoder;
-	u8 ver, hdr, cnt, len;
-	u32 data;
 	int type, ret;
 
 	switch (dcbe->type) {
@@ -1595,10 +1601,9 @@ nv50_sor_create(struct drm_connector *connector, struct dcb_output *dcbe)
 		}
 
 		if (nv_connector->type != DCB_CONNECTOR_eDP &&
-		    (data = nvbios_dp_table(bios, &ver, &hdr, &cnt, &len)) &&
-		    ver >= 0x40 && (nvbios_rd08(bios, data + 0x08) & 0x04)) {
-			ret = nv50_mstm_new(nv_encoder, &nv_connector->aux, 16,
-					    nv_connector->base.base.id,
+		    nv50_has_mst(drm)) {
+			ret = nv50_mstm_new(nv_encoder, &nv_connector->aux,
+					    16, nv_connector->base.base.id,
 					    &nv_encoder->dp.mstm);
 			if (ret)
 				return ret;
@@ -2294,6 +2299,7 @@ nv50_display_create(struct drm_device *dev)
 	struct nv50_disp *disp;
 	struct dcb_output *dcbe;
 	int crtcs, ret, i;
+	bool has_mst = nv50_has_mst(drm);
 
 	disp = kzalloc(sizeof(*disp), GFP_KERNEL);
 	if (!disp)
@@ -2342,11 +2348,25 @@ nv50_display_create(struct drm_device *dev)
 		crtcs = 0x3;
 
 	for (i = 0; i < fls(crtcs); i++) {
+		struct nv50_head *head;
+
 		if (!(crtcs & (1 << i)))
 			continue;
-		ret = nv50_head_create(dev, i);
-		if (ret)
+
+		head = nv50_head_create(dev, i);
+		if (IS_ERR(head)) {
+			ret = PTR_ERR(head);
 			goto out;
+		}
+
+		if (has_mst) {
+			head->msto = nv50_msto_new(dev, head, i);
+			if (IS_ERR(head->msto)) {
+				ret = PTR_ERR(head->msto);
+				head->msto = NULL;
+				goto out;
+			}
+		}
 	}
 
 	/* create encoder/connector objects based on VBIOS DCB table */
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.h b/drivers/gpu/drm/nouveau/dispnv50/disp.h
index 7c41b0599d1a..b16f4aa09e02 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.h
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.h
@@ -4,6 +4,8 @@
 
 #include "nouveau_display.h"
 
+struct nv50_msto;
+
 struct nv50_disp {
 	struct nvif_disp *disp;
 	struct nv50_core *core;
diff --git a/drivers/gpu/drm/nouveau/dispnv50/head.c b/drivers/gpu/drm/nouveau/dispnv50/head.c
index 71c23bf1fe25..bd2f6bf5edfd 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/head.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/head.c
@@ -474,7 +474,7 @@ nv50_head_func = {
 	.atomic_destroy_state = nv50_head_atomic_destroy_state,
 };
 
-int
+struct nv50_head *
 nv50_head_create(struct drm_device *dev, int index)
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
@@ -486,7 +486,7 @@ nv50_head_create(struct drm_device *dev, int index)
 
 	head = kzalloc(sizeof(*head), GFP_KERNEL);
 	if (!head)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	head->func = disp->core->func->head;
 	head->base.index = index;
@@ -504,7 +504,7 @@ nv50_head_create(struct drm_device *dev, int index)
 		ret = nv50_curs_new(drm, head->base.index, &curs);
 	if (ret) {
 		kfree(head);
-		return ret;
+		return ERR_PTR(ret);
 	}
 
 	crtc = &head->base.base;
@@ -519,12 +519,11 @@ nv50_head_create(struct drm_device *dev, int index)
 
 	if (head->func->olut_set) {
 		ret = nv50_lut_init(disp, &drm->client.mmu, &head->olut);
-		if (ret)
-			goto out;
+		if (ret) {
+			nv50_head_destroy(crtc);
+			return ERR_PTR(ret);
+		}
 	}
 
-out:
-	if (ret)
-		nv50_head_destroy(crtc);
-	return ret;
+	return head;
 }
diff --git a/drivers/gpu/drm/nouveau/dispnv50/head.h b/drivers/gpu/drm/nouveau/dispnv50/head.h
index d1c002f534d4..f31ef5e07f43 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/head.h
+++ b/drivers/gpu/drm/nouveau/dispnv50/head.h
@@ -11,9 +11,10 @@ struct nv50_head {
 	const struct nv50_head_func *func;
 	struct nouveau_crtc base;
 	struct nv50_lut olut;
+	struct nv50_msto *msto;
 };
 
-int nv50_head_create(struct drm_device *, int index);
+struct nv50_head *nv50_head_create(struct drm_device *, int index);
 void nv50_head_flush_set(struct nv50_head *, struct nv50_head_atom *);
 void nv50_head_flush_clr(struct nv50_head *, struct nv50_head_atom *, bool y);
 
-- 
2.21.0

[PATCH 4/4] drm/nouveau: dispnv50: Report possible_crtcs incorrectly on mstos, for now

[Lyude Paul]

This commit is seperate from the previous one to make it easier to
revert in the future. Basically, while working on making MSTOs per-head
as opposed to per-head-per-connector I discovered these lovely issues:

https://gitlab.freedesktop.org/xorg/xserver/merge_requests/277
https://gitlab.gnome.org/GNOME/mutter/issues/759

Note as well that Intel already has a temporary workaround for this in
their kernel driver. So, unfortunately we need to follow suit to avoid
causing a regression in userspace. Once these issues get fixed, this
commit should be reverted.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index d23ac13763b5..f5ad20af0dd5 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -2366,6 +2366,18 @@ nv50_display_create(struct drm_device *dev)
 				head->msto = NULL;
 				goto out;
 			}
+
+			/*
+			 * FIXME: This is a hack to workaround the following
+			 * issues:
+			 *
+			 * https://gitlab.gnome.org/GNOME/mutter/issues/759
+			 * https://gitlab.freedesktop.org/xorg/xserver/merge_requests/277
+			 *
+			 * Once these issues are closed, this should be
+			 * removed
+			 */
+			head->msto->encoder.possible_crtcs = crtcs;
 		}
 	}
 
-- 
2.21.0

Re: [PATCH 2/4] drm/nouveau: dispnv50: Remove nv50_mstc_best_encoder()

[Ilia Mirkin]

On Fri, Sep 13, 2019 at 6:05 PM Lyude Paul <lyude@redhat.com> wrote:
>
> When drm_connector_helper_funcs->atomic_best_encoder is defined,
> ->best_encoder is ignored both by the atomic modesetting helpers. That

By both the atomic modesetting helpers and ... (usually "both" implies 2 things)

> being said, this hook is completely broken anyway - it always returns
> the first msto for a given mstc, despite the fact it might already be in
> use.
>
> So, just get rid of it. We'll need this in a moment anyway, when we make
> mstos per-head as opposed to per-connector.
>
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> ---
>  drivers/gpu/drm/nouveau/dispnv50/disp.c | 9 ---------
>  1 file changed, 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index b46be8a091e9..a3f350fdfa8c 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -920,14 +920,6 @@ nv50_mstc_atomic_best_encoder(struct drm_connector *connector,
>         return &mstc->mstm->msto[head->base.index]->encoder;
>  }
>
> -static struct drm_encoder *
> -nv50_mstc_best_encoder(struct drm_connector *connector)
> -{
> -       struct nv50_mstc *mstc = nv50_mstc(connector);
> -
> -       return &mstc->mstm->msto[0]->encoder;
> -}
> -
>  static enum drm_mode_status
>  nv50_mstc_mode_valid(struct drm_connector *connector,
>                      struct drm_display_mode *mode)
> @@ -990,7 +982,6 @@ static const struct drm_connector_helper_funcs
>  nv50_mstc_help = {
>         .get_modes = nv50_mstc_get_modes,
>         .mode_valid = nv50_mstc_mode_valid,
> -       .best_encoder = nv50_mstc_best_encoder,
>         .atomic_best_encoder = nv50_mstc_atomic_best_encoder,
>         .atomic_check = nv50_mstc_atomic_check,
>  };
> --
> 2.21.0
>

Re: [PATCH 2/4] drm/nouveau: dispnv50: Remove nv50_mstc_best_encoder()

[Lyude Paul]

On Fri, 2019-09-13 at 18:20 -0400, Ilia Mirkin wrote:
> On Fri, Sep 13, 2019 at 6:05 PM Lyude Paul <lyude@redhat.com> wrote:
> > When drm_connector_helper_funcs->atomic_best_encoder is defined,
> > ->best_encoder is ignored both by the atomic modesetting helpers. That
> 
> By both the atomic modesetting helpers and ... (usually "both" implies 2
> things)

good catch, will fix and respin in a moment
> 
> > being said, this hook is completely broken anyway - it always returns
> > the first msto for a given mstc, despite the fact it might already be in
> > use.
> > 
> > So, just get rid of it. We'll need this in a moment anyway, when we make
> > mstos per-head as opposed to per-connector.
> > 
> > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > ---
> >  drivers/gpu/drm/nouveau/dispnv50/disp.c | 9 ---------
> >  1 file changed, 9 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > index b46be8a091e9..a3f350fdfa8c 100644
> > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > @@ -920,14 +920,6 @@ nv50_mstc_atomic_best_encoder(struct drm_connector
> > *connector,
> >         return &mstc->mstm->msto[head->base.index]->encoder;
> >  }
> > 
> > -static struct drm_encoder *
> > -nv50_mstc_best_encoder(struct drm_connector *connector)
> > -{
> > -       struct nv50_mstc *mstc = nv50_mstc(connector);
> > -
> > -       return &mstc->mstm->msto[0]->encoder;
> > -}
> > -
> >  static enum drm_mode_status
> >  nv50_mstc_mode_valid(struct drm_connector *connector,
> >                      struct drm_display_mode *mode)
> > @@ -990,7 +982,6 @@ static const struct drm_connector_helper_funcs
> >  nv50_mstc_help = {
> >         .get_modes = nv50_mstc_get_modes,
> >         .mode_valid = nv50_mstc_mode_valid,
> > -       .best_encoder = nv50_mstc_best_encoder,
> >         .atomic_best_encoder = nv50_mstc_atomic_best_encoder,
> >         .atomic_check = nv50_mstc_atomic_check,
> >  };
> > --
> > 2.21.0
> > 
-- 
Cheers,
	Lyude Paul

[PATCH v2] drm/nouveau: dispnv50: Remove nv50_mstc_best_encoder()

[Lyude Paul]

When drm_connector_helper_funcs->atomic_best_encoder is defined,
->best_encoder is ignored by the atomic modesetting helpers. That being
said, this hook is completely broken anyway - it always returns the
first msto for a given mstc, despite the fact it might already be in
use.

So, just get rid of it. We'll need this in a moment anyway, when we make
mstos per-head as opposed to per-connector.

Changes since v1:
* Fix typo in documentation - imirkin

Signed-off-by: Lyude Paul <lyude@redhat.com>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index b46be8a091e9..a3f350fdfa8c 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -920,14 +920,6 @@ nv50_mstc_atomic_best_encoder(struct drm_connector *connector,
 	return &mstc->mstm->msto[head->base.index]->encoder;
 }
 
-static struct drm_encoder *
-nv50_mstc_best_encoder(struct drm_connector *connector)
-{
-	struct nv50_mstc *mstc = nv50_mstc(connector);
-
-	return &mstc->mstm->msto[0]->encoder;
-}
-
 static enum drm_mode_status
 nv50_mstc_mode_valid(struct drm_connector *connector,
 		     struct drm_display_mode *mode)
@@ -990,7 +982,6 @@ static const struct drm_connector_helper_funcs
 nv50_mstc_help = {
 	.get_modes = nv50_mstc_get_modes,
 	.mode_valid = nv50_mstc_mode_valid,
-	.best_encoder = nv50_mstc_best_encoder,
 	.atomic_best_encoder = nv50_mstc_atomic_best_encoder,
 	.atomic_check = nv50_mstc_atomic_check,
 };
-- 
2.21.0