drm/i915/tv: Fix >1024 modes on gen3

On gen3 we must disable the TV encoder vertical filter for >1024
pixel wide sources. Once that's done all we can is try to center
the image on the screen. Naturally the TV mode vertical resolution
must be equal or larger than the user mode vertical resolution
or else we'd have to cut off part of the user mode.

And while we may not be able to respect the user's choice of
top and bottom borders exactly (or we'd have to reject he mode
most likely), we can try to maintain the relative sizes of the
top and bottom border with respect to each orher.

Additionally we must configure the pipe as interlaced if the
TV mode is interlaced.

v2: Make +intel_tv_connector_duplicate_state() static and drop
    the badly copy pasted kerneldoc
    s/IS_GEN3(dev_priv/IS_GEN(dev_priv, 3)/
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181112170000.27531-16-ville.syrjala@linux.intel.comReviewed-by: Imre Deak <imre.deak@intel.com>

drivers/gpu/drm/i915/intel_tv.c

@@ -860,6 +860,35 @@ static const struct tv_mode tv_modes[] = {
 	},
 };
 
+struct intel_tv_connector_state {
+	struct drm_connector_state base;
+
+	/*
+	 * May need to override the user margins for
+	 * gen3 >1024 wide source vertical centering.
+	 */
+	struct {
+		u16 top, bottom;
+	} margins;
+
+	bool bypass_vfilter;
+};
+
+#define to_intel_tv_connector_state(x) container_of(x, struct intel_tv_connector_state, base)
+
+static struct drm_connector_state *
+intel_tv_connector_duplicate_state(struct drm_connector *connector)
+{
+	struct intel_tv_connector_state *state;
+
+	state = kmemdup(connector->state, sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return NULL;
+
+	__drm_atomic_helper_connector_duplicate_state(connector, &state->base);
+	return &state->base;
+}
+
 static struct intel_tv *enc_to_tv(struct intel_encoder *encoder)
 {
 	return container_of(encoder, struct intel_tv, base);
@@ -1128,6 +1157,9 @@ intel_tv_compute_config(struct intel_encoder *encoder,
 			struct intel_crtc_state *pipe_config,
 			struct drm_connector_state *conn_state)
 {
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct intel_tv_connector_state *tv_conn_state =
+		to_intel_tv_connector_state(conn_state);
 	const struct tv_mode *tv_mode = intel_tv_mode_find(conn_state);
 	struct drm_display_mode *adjusted_mode =
 		&pipe_config->base.adjusted_mode;
@@ -1148,6 +1180,43 @@ intel_tv_compute_config(struct intel_encoder *encoder,
 	pipe_config->port_clock = tv_mode->clock;
 
 	intel_tv_mode_to_mode(adjusted_mode, tv_mode);
+	drm_mode_set_crtcinfo(adjusted_mode, 0);
+
+	if (IS_GEN(dev_priv, 3) && hdisplay > 1024) {
+		int extra, top, bottom;
+
+		extra = adjusted_mode->crtc_vdisplay - vdisplay;
+
+		if (extra < 0) {
+			DRM_DEBUG_KMS("No vertical scaling for >1024 pixel wide modes\n");
+			return false;
+		}
+
+		/* Need to turn off the vertical filter and center the image */
+
+		/* Attempt to maintain the relative sizes of the margins */
+		top = conn_state->tv.margins.top;
+		bottom = conn_state->tv.margins.bottom;
+
+		if (top + bottom)
+			top = extra * top / (top + bottom);
+		else
+			top = extra / 2;
+		bottom = extra - top;
+
+		tv_conn_state->margins.top = top;
+		tv_conn_state->margins.bottom = bottom;
+
+		tv_conn_state->bypass_vfilter = true;
+
+		if (!tv_mode->progressive)
+			adjusted_mode->flags |= DRM_MODE_FLAG_INTERLACE;
+	} else {
+		tv_conn_state->margins.top = conn_state->tv.margins.top;
+		tv_conn_state->margins.bottom = conn_state->tv.margins.bottom;
+
+		tv_conn_state->bypass_vfilter = false;
+	}
 
 	DRM_DEBUG_KMS("TV mode:\n");
 	drm_mode_debug_printmodeline(adjusted_mode);
@@ -1221,8 +1290,8 @@ intel_tv_compute_config(struct intel_encoder *encoder,
 				  conn_state->tv.margins.left,
 				  conn_state->tv.margins.right);
 	intel_tv_scale_mode_vert(adjusted_mode, vdisplay,
-				 conn_state->tv.margins.top,
-				 conn_state->tv.margins.bottom);
+				 tv_conn_state->margins.top,
+				 tv_conn_state->margins.bottom);
 	drm_mode_set_crtcinfo(adjusted_mode, 0);
 	adjusted_mode->name[0] = '\0';
 
@@ -1315,8 +1384,10 @@ static void intel_tv_pre_enable(struct intel_encoder *encoder,
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_crtc *intel_crtc = to_intel_crtc(pipe_config->base.crtc);
 	struct intel_tv *intel_tv = enc_to_tv(encoder);
+	const struct intel_tv_connector_state *tv_conn_state =
+		to_intel_tv_connector_state(conn_state);
 	const struct tv_mode *tv_mode = intel_tv_mode_find(conn_state);
-	u32 tv_ctl;
+	u32 tv_ctl, tv_filter_ctl;
 	u32 scctl1, scctl2, scctl3;
 	int i, j;
 	const struct video_levels *video_levels;
@@ -1424,16 +1495,20 @@ static void intel_tv_pre_enable(struct intel_encoder *encoder,
 	assert_pipe_disabled(dev_priv, intel_crtc->pipe);
 
 	/* Filter ctl must be set before TV_WIN_SIZE */
-	I915_WRITE(TV_FILTER_CTL_1, TV_AUTO_SCALE);
+	tv_filter_ctl = TV_AUTO_SCALE;
+	if (tv_conn_state->bypass_vfilter)
+		tv_filter_ctl |= TV_V_FILTER_BYPASS;
+	I915_WRITE(TV_FILTER_CTL_1, tv_filter_ctl);
+
 	xsize = tv_mode->hblank_start - tv_mode->hblank_end;
 	ysize = intel_tv_mode_vdisplay(tv_mode);
 
 	xpos = conn_state->tv.margins.left;
-	ypos = conn_state->tv.margins.top;
+	ypos = tv_conn_state->margins.top;
 	xsize -= (conn_state->tv.margins.left +
 		  conn_state->tv.margins.right);
-	ysize -= (conn_state->tv.margins.top +
-		  conn_state->tv.margins.bottom);
+	ysize -= (tv_conn_state->margins.top +
+		  tv_conn_state->margins.bottom);
 	I915_WRITE(TV_WIN_POS, (xpos<<16)|ypos);
 	I915_WRITE(TV_WIN_SIZE, (xsize<<16)|ysize);
 
@@ -1700,7 +1775,7 @@ static const struct drm_connector_funcs intel_tv_connector_funcs = {
 	.destroy = intel_connector_destroy,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_duplicate_state = intel_tv_connector_duplicate_state,
 };
 
 static int intel_tv_atomic_check(struct drm_connector *connector,