[PATCH 8/8] drm/i915: Bump gen7+ fb size limits to 16kx16k

[Timo Aaltonen]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

BugLink: http://bugs.launchpad.net/bugs/1714178

With gtt remapping in place we can use arbitrarily large
framebuffers. Let's bump the limits to 16kx16k on gen7+.
The limit was chosen to match the maximum 2D surface size
of the 3D engine.

With the remapping we could easily go higher than that for the
display engine. However the modesetting ddx will blindly assume
it can handle whatever is reported via kms. The oversized
buffer dimensions are not caught by glamor nor Mesa until
finally an assert will trip when genxml attempts to pack the
SURFACE_STATE. So we pick a safe limit to avoid the X server
from crashing (or potentially misbehaving if the genxml asserts
are compiled out).

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110187
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190509122159.24376-9-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
(cherry picked from commit 5c000fb33b767c3fa10d29a1021edbf4f92b76a2)
Signed-off-by: Timo Aaltonen <timo.aaltonen at canonical.com>
---
 drivers/gpu/drm/i915/intel_display.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 89196b876037..0fc7f245fb7e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15760,16 +15760,22 @@ int intel_modeset_init(struct drm_device *dev)
 		}
 	}
 
-	/* maximum framebuffer dimensions */
-	if (IS_GEN(dev_priv, 2)) {
-		dev->mode_config.max_width = 2048;
-		dev->mode_config.max_height = 2048;
+	/*
+	 * Maximum framebuffer dimensions, chosen to match
+	 * the maximum render engine surface size on gen4+.
+	 */
+	if (INTEL_GEN(dev_priv) >= 7) {
+		dev->mode_config.max_width = 16384;
+		dev->mode_config.max_height = 16384;
+	} else if (INTEL_GEN(dev_priv) >= 4) {
+		dev->mode_config.max_width = 8192;
+		dev->mode_config.max_height = 8192;
 	} else if (IS_GEN(dev_priv, 3)) {
 		dev->mode_config.max_width = 4096;
 		dev->mode_config.max_height = 4096;
 	} else {
-		dev->mode_config.max_width = 8192;
-		dev->mode_config.max_height = 8192;
+		dev->mode_config.max_width = 2048;
+		dev->mode_config.max_height = 2048;
 	}
 
 	if (IS_I845G(dev_priv) || IS_I865G(dev_priv)) {
-- 
2.20.1