From 05b3c681ea2f478c0cb941c2f8279919cf78de6d Mon Sep 17 00:00:00 2001
From: Daniel Strnad <strnadda@gmail.com>
Date: Tue, 19 May 2020 15:52:35 +0200
Subject: [PATCH] hw/xfree86: Propagate physical dimensions from DRM connector

Physical dimmension of display can be obtained not just by configuration or
DDC, but also directly from kernel via drmModeGetConnector(). Until now
xserver silently discarded these values even when no configuration nor EDID
were present and fallbacked to default DPI.
---
 hw/xfree86/common/xf86Helper.c | 30 ++++++++++++++++++------------
 hw/xfree86/modes/xf86Crtc.c    |  6 ++++--
 hw/xfree86/modes/xf86RandR12.c |  6 ++++++
 3 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/hw/xfree86/common/xf86Helper.c b/hw/xfree86/common/xf86Helper.c
index 0389945a7..d03382d26 100644
--- a/hw/xfree86/common/xf86Helper.c
+++ b/hw/xfree86/common/xf86Helper.c
@@ -55,6 +55,7 @@
 #include "xf86Xinput.h"
 #include "xf86InPriv.h"
 #include "mivalidate.h"
+#include "xf86Crtc.h"
 
 /* For xf86GetClocks */
 #if defined(CSRG_BASED) || defined(__GNU__)
@@ -851,8 +852,9 @@ xf86SetDpi(ScrnInfoPtr pScrn, int x, int y)
 {
     MessageType from = X_DEFAULT;
     xf86MonPtr DDC = (xf86MonPtr) (pScrn->monitor->DDC);
-    int ddcWidthmm, ddcHeightmm;
+    int probedWidthmm, probedHeightmm;
     int widthErr, heightErr;
+    xf86OutputPtr compat = xf86CompatOutput(pScrn);
 
     /* XXX Maybe there is no need for widthmm/heightmm in ScrnInfoRec */
     pScrn->widthmm = pScrn->monitor->widthmm;
@@ -862,11 +864,15 @@ xf86SetDpi(ScrnInfoPtr pScrn, int x, int y)
         /* DDC gives display size in mm for individual modes,
          * but cm for monitor
          */
-        ddcWidthmm = DDC->features.hsize * 10;  /* 10mm in 1cm */
-        ddcHeightmm = DDC->features.vsize * 10; /* 10mm in 1cm */
+        probedWidthmm = DDC->features.hsize * 10;  /* 10mm in 1cm */
+        probedHeightmm = DDC->features.vsize * 10; /* 10mm in 1cm */
+    }
+    else if (compat && compat->mm_width > 0 && compat->mm_height > 0) {
+        probedWidthmm = compat->mm_width;
+        probedHeightmm = compat->mm_height;
     }
     else {
-        ddcWidthmm = ddcHeightmm = 0;
+        probedWidthmm = probedHeightmm = 0;
     }
 
     if (monitorResolution > 0) {
@@ -892,15 +898,15 @@ xf86SetDpi(ScrnInfoPtr pScrn, int x, int y)
                    pScrn->widthmm, pScrn->heightmm);
 
         /* Warn if config and probe disagree about display size */
-        if (ddcWidthmm && ddcHeightmm) {
+        if (probedWidthmm && probedHeightmm) {
             if (pScrn->widthmm > 0) {
-                widthErr = abs(ddcWidthmm - pScrn->widthmm);
+                widthErr = abs(probedWidthmm - pScrn->widthmm);
             }
             else {
                 widthErr = 0;
             }
             if (pScrn->heightmm > 0) {
-                heightErr = abs(ddcHeightmm - pScrn->heightmm);
+                heightErr = abs(probedHeightmm - pScrn->heightmm);
             }
             else {
                 heightErr = 0;
@@ -909,17 +915,17 @@ xf86SetDpi(ScrnInfoPtr pScrn, int x, int y)
                 /* Should include config file name for monitor here */
                 xf86DrvMsg(pScrn->scrnIndex, X_WARNING,
                            "Probed monitor is %dx%d mm, using Displaysize %dx%d mm\n",
-                           ddcWidthmm, ddcHeightmm, pScrn->widthmm,
+                           probedWidthmm, probedHeightmm, pScrn->widthmm,
                            pScrn->heightmm);
             }
         }
     }
-    else if (ddcWidthmm && ddcHeightmm) {
+    else if (probedWidthmm && probedHeightmm) {
         from = X_PROBED;
         xf86DrvMsg(pScrn->scrnIndex, from, "Display dimensions: (%d, %d) mm\n",
-                   ddcWidthmm, ddcHeightmm);
-        pScrn->widthmm = ddcWidthmm;
-        pScrn->heightmm = ddcHeightmm;
+                   probedWidthmm, probedHeightmm);
+        pScrn->widthmm = probedWidthmm;
+        pScrn->heightmm = probedHeightmm;
         if (pScrn->widthmm > 0) {
             pScrn->xDpi =
                 (int) ((double) pScrn->virtualX * MMPERINCH / pScrn->widthmm);
diff --git a/hw/xfree86/modes/xf86Crtc.c b/hw/xfree86/modes/xf86Crtc.c
index c6e89e66f..202791774 100644
--- a/hw/xfree86/modes/xf86Crtc.c
+++ b/hw/xfree86/modes/xf86Crtc.c
@@ -3256,8 +3256,10 @@ xf86OutputSetEDID(xf86OutputPtr output, xf86MonPtr edid_mon)
     free(output->MonInfo);
 
     output->MonInfo = edid_mon;
-    output->mm_width = 0;
-    output->mm_height = 0;
+    if (edid_mon) {
+        output->mm_width = 0;
+        output->mm_height = 0;
+    }
 
     if (debug_modes) {
         xf86DrvMsg(scrn->scrnIndex, X_INFO, "EDID for output %s\n",
diff --git a/hw/xfree86/modes/xf86RandR12.c b/hw/xfree86/modes/xf86RandR12.c
index 50cbd043e..d4651f4e8 100644
--- a/hw/xfree86/modes/xf86RandR12.c
+++ b/hw/xfree86/modes/xf86RandR12.c
@@ -806,6 +806,12 @@ xf86RandR12CreateScreenResources(ScreenPtr pScreen)
                 mmWidth = output->conf_monitor->mon_width;
                 mmHeight = output->conf_monitor->mon_height;
             }
+            else if (output &&
+                (output->mm_width > 0 &&
+                 output->mm_height > 0)) {
+                mmWidth = output->mm_width;
+                mmHeight = output->mm_height;
+            }
             else {
                 /*
                  * Otherwise, just set the screen to DEFAULT_DPI
-- 
2.26.2