Nouveau - May 2018 - [PATCH v2 2/4] drm/vc4: Take underscan setup into account when updating planes

On Fri, May 11, 2018 at 05:52:56PM +0200, Boris Brezillon
wrote:
> On Fri, 11 May 2018 18:34:50 +0300
> Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> 
> > On Fri, May 11, 2018 at 04:59:17PM +0200, Boris Brezillon wrote:
> > > Applying an underscan setup is just a matter of scaling all
planes
> > > appropriately and adjusting the CRTC X/Y offset to account for
the
> > > horizontal and vertical border.
> > > 
> > > Create an vc4_plane_underscan_adj() function doing that and call
it from
> > > vc4_plane_setup_clipping_and_scaling() so that we are ready to
attach
> > > underscan properties to the HDMI connector.
> > > 
> > > Signed-off-by: Boris Brezillon <boris.brezillon at
bootlin.com>
> > > ---
> > > Changes in v2:
> > > - Take changes on hborder/vborder meaning into account
> > > ---
> > >  drivers/gpu/drm/vc4/vc4_plane.c | 49
++++++++++++++++++++++++++++++++++++++++-
> > >  1 file changed, 48 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/vc4/vc4_plane.c
b/drivers/gpu/drm/vc4/vc4_plane.c
> > > index 71d44c357d35..61ed60841cd6 100644
> > > --- a/drivers/gpu/drm/vc4/vc4_plane.c
> > > +++ b/drivers/gpu/drm/vc4/vc4_plane.c
> > > @@ -258,6 +258,49 @@ static u32 vc4_get_scl_field(struct
drm_plane_state *state, int plane)
> > >  	}
> > >  }
> > >  
> > > +static int vc4_plane_underscan_adj(struct drm_plane_state
*pstate)
> > > +{
> > > +	struct vc4_plane_state *vc4_pstate =
to_vc4_plane_state(pstate);
> > > +	struct drm_connector_state *conn_state = NULL;
> > > +	struct drm_connector *conn;
> > > +	struct drm_crtc_state *crtc_state;
> > > +	int i;
> > > +
> > > +	for_each_new_connector_in_state(pstate->state, conn,
conn_state, i) {
> > > +		if (conn_state->crtc == pstate->crtc)
> > > +			break;
> > > +	}
> > > +
> > > +	if (i == pstate->state->num_connector)
> > > +		return 0;
> > > +
> > > +	if (conn_state->underscan.mode != DRM_UNDERSCAN_ON)
> > > +		return 0;
> > > +
> > > +	crtc_state = drm_atomic_get_new_crtc_state(pstate->state,
> > > +						   pstate->crtc);
> > > +
> > > +	if (conn_state->underscan.hborder >=
crtc_state->mode.hdisplay ||
> > > +	    conn_state->underscan.vborder >=
crtc_state->mode.vdisplay)
> > > +		return -EINVAL;  
> > 
> > border * 2 ?
> 
> Oops, indeed. I'll fix that.
> 
> > 
> > > +
> > > +	vc4_pstate->crtc_x += conn_state->underscan.hborder;
> > > +	vc4_pstate->crtc_y += conn_state->underscan.vborder;
> > > +	vc4_pstate->crtc_w = (vc4_pstate->crtc_w *
> > > +			      (crtc_state->mode.hdisplay -
> > > +			       (conn_state->underscan.hborder * 2))) /
> > > +			     crtc_state->mode.hdisplay;
> > > +	vc4_pstate->crtc_h = (vc4_pstate->crtc_h *
> > > +			      (crtc_state->mode.vdisplay -
> > > +			       (conn_state->underscan.vborder * 2))) /
> > > +			     crtc_state->mode.vdisplay;  
> > 
> > So you're now scaling all planes? The code seems to reject scaling
for
> > the cursor plane, how are you dealing with that? Or just no cursor
> > allowed when underscanning?
> 
> No, I just didn't test with a cursor plane. We should probably avoid
> scaling the cursor plane and just adjust its position. Eric any opinion
> on that?
I don't think you can just not scale it. The user asked for the cursor
to be at a specific place with a specific size. Can't just ignore
that and do something else. Also eg. i915 would definitely scale the
cursor since we'd just scale the entire crtc instead of scaling
individual planes. Different drivers doing different things wouldn't
be good.
> 
> > 
> > I'm also wondering if there's any way we can reconcile these
border
> > props with the scaling mode prop, should we ever wish to expose
> > these props on connectors that already have the scaling mode prop.
> 
> Nouveau seems to expose both, and I don't see why we couldn't.
First of all the interaction of these borders with panels that have
a fixed mode would need to be properly specified. Do we apply the
borders against the user mode or the panel's native mode? I guess
the latter would be a bit easier (would also match how the TV margins
behave I suppose). But that does leave open the question of how
would generic userspace know which case it's dealing with? Eg. if it
wants to underscan by some specific percentage it has to calculate
the borders based on the correct mode, otherwise the results aren't
going to match the expectations.
> 
> > Maybe we just have to require the scaling mode to be set to fullscreen
> > to allow borders to be specified explictly?
> > 
> > > +
> > > +	if (!vc4_pstate->crtc_w || !vc4_pstate->crtc_h)
> > > +		return -EINVAL;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >  static int vc4_plane_setup_clipping_and_scaling(struct
drm_plane_state *state)
> > >  {
> > >  	struct drm_plane *plane = state->plane;
> > > @@ -269,7 +312,7 @@ static int
vc4_plane_setup_clipping_and_scaling(struct drm_plane_state *state)
> > >  	int num_planes = fb->format->num_planes;
> > >  	u32 h_subsample = 1;
> > >  	u32 v_subsample = 1;
> > > -	int i;
> > > +	int i, ret;
> > >  
> > >  	for (i = 0; i < num_planes; i++)
> > >  		vc4_state->offsets[i] = bo->paddr + fb->offsets[i];
> > > @@ -292,6 +335,10 @@ static int
vc4_plane_setup_clipping_and_scaling(struct drm_plane_state *state)
> > >  	vc4_state->crtc_w = state->crtc_w;
> > >  	vc4_state->crtc_h = state->crtc_h;
> > >  
> > > +	ret = vc4_plane_underscan_adj(state);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > >  	vc4_state->x_scaling[0] =
vc4_get_scaling_mode(vc4_state->src_w[0],
> > >  						       vc4_state->crtc_w);
> > >  	vc4_state->y_scaling[0] =
vc4_get_scaling_mode(vc4_state->src_h[0],
> > > -- 
> > > 2.14.1
> > > 
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel at lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel  
> > 
-- 
Ville Syrjälä
Intel

On Fri, 11 May 2018 19:54:02 +0300
Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Fri, May 11, 2018 at 05:52:56PM +0200, Boris Brezillon wrote:
> > On Fri, 11 May 2018 18:34:50 +0300
> > Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> >   
> > > On Fri, May 11, 2018 at 04:59:17PM +0200, Boris Brezillon wrote:
> > > > Applying an underscan setup is just a matter of scaling all
planes
> > > > appropriately and adjusting the CRTC X/Y offset to account
for the
> > > > horizontal and vertical border.
> > > > 
> > > > Create an vc4_plane_underscan_adj() function doing that and
call it from
> > > > vc4_plane_setup_clipping_and_scaling() so that we are ready
to attach
> > > > underscan properties to the HDMI connector.
> > > > 
> > > > Signed-off-by: Boris Brezillon <boris.brezillon at
bootlin.com>
> > > > ---
> > > > Changes in v2:
> > > > - Take changes on hborder/vborder meaning into account
> > > > ---
> > > >  drivers/gpu/drm/vc4/vc4_plane.c | 49
++++++++++++++++++++++++++++++++++++++++-
> > > >  1 file changed, 48 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/vc4/vc4_plane.c
b/drivers/gpu/drm/vc4/vc4_plane.c
> > > > index 71d44c357d35..61ed60841cd6 100644
> > > > --- a/drivers/gpu/drm/vc4/vc4_plane.c
> > > > +++ b/drivers/gpu/drm/vc4/vc4_plane.c
> > > > @@ -258,6 +258,49 @@ static u32 vc4_get_scl_field(struct
drm_plane_state *state, int plane)
> > > >  	}
> > > >  }
> > > >  
> > > > +static int vc4_plane_underscan_adj(struct drm_plane_state
*pstate)
> > > > +{
> > > > +	struct vc4_plane_state *vc4_pstate =
to_vc4_plane_state(pstate);
> > > > +	struct drm_connector_state *conn_state = NULL;
> > > > +	struct drm_connector *conn;
> > > > +	struct drm_crtc_state *crtc_state;
> > > > +	int i;
> > > > +
> > > > +	for_each_new_connector_in_state(pstate->state, conn,
conn_state, i) {
> > > > +		if (conn_state->crtc == pstate->crtc)
> > > > +			break;
> > > > +	}
> > > > +
> > > > +	if (i == pstate->state->num_connector)
> > > > +		return 0;
> > > > +
> > > > +	if (conn_state->underscan.mode != DRM_UNDERSCAN_ON)
> > > > +		return 0;
> > > > +
> > > > +	crtc_state =
drm_atomic_get_new_crtc_state(pstate->state,
> > > > +						   pstate->crtc);
> > > > +
> > > > +	if (conn_state->underscan.hborder >=
crtc_state->mode.hdisplay ||
> > > > +	    conn_state->underscan.vborder >=
crtc_state->mode.vdisplay)
> > > > +		return -EINVAL;    
> > > 
> > > border * 2 ?  
> > 
> > Oops, indeed. I'll fix that.
> >   
> > >   
> > > > +
> > > > +	vc4_pstate->crtc_x += conn_state->underscan.hborder;
> > > > +	vc4_pstate->crtc_y += conn_state->underscan.vborder;
> > > > +	vc4_pstate->crtc_w = (vc4_pstate->crtc_w *
> > > > +			      (crtc_state->mode.hdisplay -
> > > > +			       (conn_state->underscan.hborder * 2))) /
> > > > +			     crtc_state->mode.hdisplay;
> > > > +	vc4_pstate->crtc_h = (vc4_pstate->crtc_h *
> > > > +			      (crtc_state->mode.vdisplay -
> > > > +			       (conn_state->underscan.vborder * 2))) /
> > > > +			     crtc_state->mode.vdisplay;    
> > > 
> > > So you're now scaling all planes? The code seems to reject
scaling for
> > > the cursor plane, how are you dealing with that? Or just no
cursor
> > > allowed when underscanning?  
> > 
> > No, I just didn't test with a cursor plane. We should probably
avoid
> > scaling the cursor plane and just adjust its position. Eric any
opinion
> > on that?  
> 
> I don't think you can just not scale it. The user asked for the cursor
> to be at a specific place with a specific size. Can't just ignore
> that and do something else. Also eg. i915 would definitely scale the
> cursor since we'd just scale the entire crtc instead of scaling
> individual planes. Different drivers doing different things wouldn't
> be good.
Except in our case the scaling takes place before the composition, so
we don't have a choice.
> 
> >   
> > > 
> > > I'm also wondering if there's any way we can reconcile
these border
> > > props with the scaling mode prop, should we ever wish to expose
> > > these props on connectors that already have the scaling mode
prop.
> > 
> > Nouveau seems to expose both, and I don't see why we couldn't.
> 
> First of all the interaction of these borders with panels that have
> a fixed mode would need to be properly specified. Do we apply the
> borders against the user mode or the panel's native mode?
Hm, I'm a bit lost. Isn't crtc_state->mode supposed to contain the
mode
that is about to be applied, no matter if it's a usermode or one of the
mode returned by the display? 
> I guess
> the latter would be a bit easier (would also match how the TV margins
> behave I suppose). But that does leave open the question of how
> would generic userspace know which case it's dealing with? Eg. if it
> wants to underscan by some specific percentage it has to calculate
> the borders based on the correct mode, otherwise the results aren't
> going to match the expectations.
I don't get it, sorry. Borders are relative to the mode applied by
userspace. So if it needs to express borders as a ratio of the
resolution, then for sure userspace will have to do the math, but I
don't see the problem here.

On Fri, May 11, 2018 at 07:12:21PM +0200, Boris Brezillon
wrote:
> On Fri, 11 May 2018 19:54:02 +0300
> Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> 
> > On Fri, May 11, 2018 at 05:52:56PM +0200, Boris Brezillon wrote:
> > > On Fri, 11 May 2018 18:34:50 +0300
> > > Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> > >   
> > > > On Fri, May 11, 2018 at 04:59:17PM +0200, Boris Brezillon
wrote:
> > > > > Applying an underscan setup is just a matter of scaling
all planes
> > > > > appropriately and adjusting the CRTC X/Y offset to
account for the
> > > > > horizontal and vertical border.
> > > > > 
> > > > > Create an vc4_plane_underscan_adj() function doing that
and call it from
> > > > > vc4_plane_setup_clipping_and_scaling() so that we are
ready to attach
> > > > > underscan properties to the HDMI connector.
> > > > > 
> > > > > Signed-off-by: Boris Brezillon <boris.brezillon at
bootlin.com>
> > > > > ---
> > > > > Changes in v2:
> > > > > - Take changes on hborder/vborder meaning into account
> > > > > ---
> > > > >  drivers/gpu/drm/vc4/vc4_plane.c | 49
++++++++++++++++++++++++++++++++++++++++-
> > > > >  1 file changed, 48 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/vc4/vc4_plane.c
b/drivers/gpu/drm/vc4/vc4_plane.c
> > > > > index 71d44c357d35..61ed60841cd6 100644
> > > > > --- a/drivers/gpu/drm/vc4/vc4_plane.c
> > > > > +++ b/drivers/gpu/drm/vc4/vc4_plane.c
> > > > > @@ -258,6 +258,49 @@ static u32
vc4_get_scl_field(struct drm_plane_state *state, int plane)
> > > > >  	}
> > > > >  }
> > > > >  
> > > > > +static int vc4_plane_underscan_adj(struct
drm_plane_state *pstate)
> > > > > +{
> > > > > +	struct vc4_plane_state *vc4_pstate =
to_vc4_plane_state(pstate);
> > > > > +	struct drm_connector_state *conn_state = NULL;
> > > > > +	struct drm_connector *conn;
> > > > > +	struct drm_crtc_state *crtc_state;
> > > > > +	int i;
> > > > > +
> > > > > +	for_each_new_connector_in_state(pstate->state,
conn, conn_state, i) {
> > > > > +		if (conn_state->crtc == pstate->crtc)
> > > > > +			break;
> > > > > +	}
> > > > > +
> > > > > +	if (i == pstate->state->num_connector)
> > > > > +		return 0;
> > > > > +
> > > > > +	if (conn_state->underscan.mode !=
DRM_UNDERSCAN_ON)
> > > > > +		return 0;
> > > > > +
> > > > > +	crtc_state =
drm_atomic_get_new_crtc_state(pstate->state,
> > > > > +						   pstate->crtc);
> > > > > +
> > > > > +	if (conn_state->underscan.hborder >=
crtc_state->mode.hdisplay ||
> > > > > +	    conn_state->underscan.vborder >=
crtc_state->mode.vdisplay)
> > > > > +		return -EINVAL;    
> > > > 
> > > > border * 2 ?  
> > > 
> > > Oops, indeed. I'll fix that.
> > >   
> > > >   
> > > > > +
> > > > > +	vc4_pstate->crtc_x +=
conn_state->underscan.hborder;
> > > > > +	vc4_pstate->crtc_y +=
conn_state->underscan.vborder;
> > > > > +	vc4_pstate->crtc_w = (vc4_pstate->crtc_w *
> > > > > +			      (crtc_state->mode.hdisplay -
> > > > > +			       (conn_state->underscan.hborder * 2))) /
> > > > > +			     crtc_state->mode.hdisplay;
> > > > > +	vc4_pstate->crtc_h = (vc4_pstate->crtc_h *
> > > > > +			      (crtc_state->mode.vdisplay -
> > > > > +			       (conn_state->underscan.vborder * 2))) /
> > > > > +			     crtc_state->mode.vdisplay;    
> > > > 
> > > > So you're now scaling all planes? The code seems to
reject scaling for
> > > > the cursor plane, how are you dealing with that? Or just no
cursor
> > > > allowed when underscanning?  
> > > 
> > > No, I just didn't test with a cursor plane. We should
probably avoid
> > > scaling the cursor plane and just adjust its position. Eric any
opinion
> > > on that?  
> > 
> > I don't think you can just not scale it. The user asked for the
cursor
> > to be at a specific place with a specific size. Can't just ignore
> > that and do something else. Also eg. i915 would definitely scale the
> > cursor since we'd just scale the entire crtc instead of scaling
> > individual planes. Different drivers doing different things
wouldn't
> > be good.
> 
> Except in our case the scaling takes place before the composition, so
> we don't have a choice.
The choice is to either do what userspace asked, or return an error.
> 
> > 
> > >   
> > > > 
> > > > I'm also wondering if there's any way we can
reconcile these border
> > > > props with the scaling mode prop, should we ever wish to
expose
> > > > these props on connectors that already have the scaling mode
prop.
> > > 
> > > Nouveau seems to expose both, and I don't see why we
couldn't.
> > 
> > First of all the interaction of these borders with panels that have
> > a fixed mode would need to be properly specified. Do we apply the
> > borders against the user mode or the panel's native mode?
> 
> Hm, I'm a bit lost. Isn't crtc_state->mode supposed to contain
the mode
> that is about to be applied, no matter if it's a usermode or one of the
> mode returned by the display? 
No. With fixed mode panels the user mode is a lie. Only
hdisplay/vdisplay mean anything. The actual timings are known only to
the kernel. Well, userspace can perhaps make an educated guess based on
the connector's mode list and the presence of the scaling mode property.
> 
> > I guess
> > the latter would be a bit easier (would also match how the TV margins
> > behave I suppose). But that does leave open the question of how
> > would generic userspace know which case it's dealing with? Eg. if
it
> > wants to underscan by some specific percentage it has to calculate
> > the borders based on the correct mode, otherwise the results
aren't
> > going to match the expectations.
> 
> I don't get it, sorry. Borders are relative to the mode applied by
> userspace. So if it needs to express borders as a ratio of the
> resolution, then for sure userspace will have to do the math, but I
> don't see the problem here.
-- 
Ville Syrjälä
Intel