drm/i915: Don't advertise modes that exceed the max plane size

Modern platforms allow the transcoders hdisplay/vdisplay to exceed the
planes' max resolution. This has the nasty implication that modes on the
connectors' mode list may not be usable when the user asks for a
fullscreen plane. Seeing as that is the most common use case it seems
prudent to filter out modes that don't allow for fullscreen planes to
be enabled.

Let's do that in the connetor .mode_valid() hook so that normally
such modes are kept hidden but the user is still able to forcibly
specify such a mode if they know they don't need fullscreen planes.

This is in line with ealier policies regarding certain clock limits.
The idea is to prevent the casual user from encountering a mode that
would fail under typical conditions, but allow the expert user to
force things if they so wish.

Maybe in the future we should consider automagically using two
planes when one can't cover the entire screen? Wouldn't be a
great match for the current uapi with explicit planes though,
but I guess no worse than using two pipes (which we apparently
have to in the future anyway). Either that or we'd have to
teach userspace to do it for us.

v2: Fix icl+ max plane heigth (Manasi)

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Leho Kraav <leho@kraav.com>
Cc: Sean Paul <sean@poorly.run>
Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190918150707.32420-1-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -15753,6 +15753,7 @@ intel_mode_valid(struct drm_device *dev,
 			   DRM_MODE_FLAG_CLKDIV2))
 		return MODE_BAD;
 
+	/* Transcoder timing limits */
 	if (INTEL_GEN(dev_priv) >= 11) {
 		hdisplay_max = 16384;
 		vdisplay_max = 8192;
@@ -15791,6 +15792,41 @@ intel_mode_valid(struct drm_device *dev,
 	return MODE_OK;
 }
 
+enum drm_mode_status
+intel_mode_valid_max_plane_size(struct drm_i915_private *dev_priv,
+				const struct drm_display_mode *mode)
+{
+	int plane_width_max, plane_height_max;
+
+	/*
+	 * intel_mode_valid() should be
+	 * sufficient on older platforms.
+	 */
+	if (INTEL_GEN(dev_priv) < 9)
+		return MODE_OK;
+
+	/*
+	 * Most people will probably want a fullscreen
+	 * plane so let's not advertize modes that are
+	 * too big for that.
+	 */
+	if (INTEL_GEN(dev_priv) >= 11) {
+		plane_width_max = 5120;
+		plane_height_max = 4320;
+	} else {
+		plane_width_max = 5120;
+		plane_height_max = 4096;
+	}
+
+	if (mode->hdisplay > plane_width_max)
+		return MODE_H_ILLEGAL;
+
+	if (mode->vdisplay > plane_height_max)
+		return MODE_V_ILLEGAL;
+
+	return MODE_OK;
+}
+
 static const struct drm_mode_config_funcs intel_mode_funcs = {
 	.fb_create = intel_user_framebuffer_create,
 	.get_format_info = intel_get_format_info,

drivers/gpu/drm/i915/display/intel_display.h

@@ -32,6 +32,7 @@ enum link_m_n_set;
 struct dpll;
 struct drm_connector;
 struct drm_device;
+struct drm_display_mode;
 struct drm_encoder;
 struct drm_file;
 struct drm_format_info;
@@ -448,6 +449,9 @@ void lpt_disable_clkout_dp(struct drm_i915_private *dev_priv);
 u32 intel_plane_fb_max_stride(struct drm_i915_private *dev_priv,
 			      u32 pixel_format, u64 modifier);
 bool intel_plane_can_remap(const struct intel_plane_state *plane_state);
+enum drm_mode_status
+intel_mode_valid_max_plane_size(struct drm_i915_private *dev_priv,
+				const struct drm_display_mode *mode);
 enum phy intel_port_to_phy(struct drm_i915_private *i915, enum port port);
 
 void intel_plane_destroy(struct drm_plane *plane);

drivers/gpu/drm/i915/display/intel_dp.c

@@ -562,7 +562,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
 	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
 		return MODE_H_ILLEGAL;
 
-	return MODE_OK;
+	return intel_mode_valid_max_plane_size(dev_priv, mode);
 }
 
 u32 intel_dp_pack_aux(const u8 *src, int src_bytes)

drivers/gpu/drm/i915/display/intel_dsi.c

@@ -55,6 +55,7 @@ int intel_dsi_get_modes(struct drm_connector *connector)
 enum drm_mode_status intel_dsi_mode_valid(struct drm_connector *connector,
 					  struct drm_display_mode *mode)
 {
+	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	struct intel_connector *intel_connector = to_intel_connector(connector);
 	const struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;
 	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
@@ -73,7 +74,7 @@ enum drm_mode_status intel_dsi_mode_valid(struct drm_connector *connector,
 			return MODE_CLOCK_HIGH;
 	}
 
-	return MODE_OK;
+	return intel_mode_valid_max_plane_size(dev_priv, mode);
 }
 
 struct intel_dsi_host *intel_dsi_host_init(struct intel_dsi *intel_dsi,

drivers/gpu/drm/i915/display/intel_hdmi.c

@@ -2188,8 +2188,10 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
 			status = hdmi_port_clock_valid(hdmi, clock * 5 / 4,
 						       true, force_dvi);
 	}
+	if (status != MODE_OK)
+		return status;
 
-	return status;
+	return intel_mode_valid_max_plane_size(dev_priv, mode);
 }
 
 static bool hdmi_deep_color_possible(const struct intel_crtc_state *crtc_state,