sna: Use physical output size from the kernel

We have a conflict between Xorg and the kernel, once again, over the
meaning of the EDID. Since the kernel supplies us with the physical size
of the connector, let's place the burden of trust on the kernel and
ignore the quirky behaviour of Xorg.

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=96255
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 24 insertions, 1 deletions

diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c
index 9c1d8fda..3a627a46 100644
--- a/src/sna/sna_display.c
+++ b/src/sna/sna_display.c
@@ -3445,6 +3445,8 @@ sna_output_detect(xf86OutputPtr output)
 	switch (compat_conn.conn.connection) {
 	case DRM_MODE_CONNECTED:
 		sna_output->status = XF86OutputStatusConnected;
+		output->mm_width = compat_conn.conn.mm_width;
+		output->mm_height = compat_conn.conn.mm_height;
 		break;
 	case DRM_MODE_DISCONNECTED:
 		sna_output->status = XF86OutputStatusDisconnected;
@@ -3487,6 +3489,27 @@ sna_output_mode_valid(xf86OutputPtr output, DisplayModePtr mode)
 	return MODE_OK;
 }
 
+static void sna_output_set_parsed_edid(xf86OutputPtr output, xf86MonPtr mon)
+{
+	unsigned conn_mm_width, conn_mm_height;
+
+	/* We set the output size based on values from the kernel */
+	conn_mm_width = output->mm_width;
+	conn_mm_height = output->mm_height;
+
+	xf86OutputSetEDID(output, mon);
+
+	if (output->mm_width != conn_mm_width || output->mm_height != conn_mm_height) {
+		DBG(("%s)%s): kernel and Xorg disagree over physical size: kernel=%dx%dmm, Xorg=%dx%dmm\n",
+		     __FUNCION__, output->name,
+		     conn_mm_width, conn_mm_height,
+		     output->mm_width, output->mm_height));
+	}
+
+	output->mm_width = conn_mm_width;
+	output->mm_height = conn_mm_height;
+}
+
 static void
 sna_output_attach_edid(xf86OutputPtr output)
 {
@@ -3594,7 +3617,7 @@ skip_read:
 	}
 
 done:
-	xf86OutputSetEDID(output, mon);
+	sna_output_set_parsed_edid(output, mon);
 	if (raw) {
 		sna_output->edid_raw = raw;
 		sna_output->edid_len = blob.length;