From 7c5b5642b2abf7d67e1ce04b75d85915faa34f4c Mon Sep 17 00:00:00 2001
From: Tom Yan <tom.ty89@gmail.com>
Date: Thu, 20 Jan 2022 22:25:07 +0800
Subject: [PATCH] mi: decouple miCreateScreenResources from
 pScreen->{width,height}

This allows pScreen->{width,height} to be changed to smaller values
after miScreenInit() is called but before pScreen is further set up
/ used by dix, so that the screen size can be fit to the mode of
choice even when it does not have the maximum width and/or height
among its peers.

XGetImage() for one will fail once the screen is change back to a
bigger size with xrandr, which prevents e.g. x11vnc to work on the
server.

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/854>
---
 mi/miscrinit.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/mi/miscrinit.c b/mi/miscrinit.c
index f375d19fa..2030674a9 100644
--- a/mi/miscrinit.c
+++ b/mi/miscrinit.c
@@ -55,6 +55,8 @@ from The Open Group.
 typedef struct {
     void *pbits;                /* pointer to framebuffer */
     int width;                  /* delta to add to a framebuffer addr to move one row down */
+    int xsize;
+    int ysize;
 } miScreenInitParmsRec, *miScreenInitParmsPtr;
 
 /* this plugs into pScreen->ModifyPixmapHeader */
@@ -166,8 +168,8 @@ miCreateScreenResources(ScreenPtr pScreen)
         if (!pPixmap)
             return FALSE;
 
-        if (!(*pScreen->ModifyPixmapHeader) (pPixmap, pScreen->width,
-                                             pScreen->height,
+        if (!(*pScreen->ModifyPixmapHeader) (pPixmap, pScrInitParms->xsize,
+                                             pScrInitParms->ysize,
                                              pScreen->rootDepth,
                                              BitsPerPixel(pScreen->rootDepth),
                                              PixmapBytePad(pScrInitParms->width,
@@ -185,7 +187,7 @@ miCreateScreenResources(ScreenPtr pScreen)
 }
 
 static Bool
-miScreenDevPrivateInit(ScreenPtr pScreen, int width, void *pbits)
+miScreenDevPrivateInit(ScreenPtr pScreen, int width, void *pbits, int xsize, int ysize)
 {
     miScreenInitParmsPtr pScrInitParms;
 
@@ -198,6 +200,8 @@ miScreenDevPrivateInit(ScreenPtr pScreen, int width, void *pbits)
         return FALSE;
     pScrInitParms->pbits = pbits;
     pScrInitParms->width = width;
+    pScrInitParms->xsize = xsize;
+    pScrInitParms->ysize = ysize;
     pScreen->devPrivate = (void *) pScrInitParms;
     return TRUE;
 }
@@ -291,7 +295,7 @@ miScreenInit(ScreenPtr pScreen, void *pbits,  /* pointer to screen bits */
 
     miSetZeroLineBias(pScreen, DEFAULTZEROLINEBIAS);
 
-    return miScreenDevPrivateInit(pScreen, width, pbits);
+    return miScreenDevPrivateInit(pScreen, width, pbits, xsize, ysize);
 }
 
 DevPrivateKeyRec miZeroLineScreenKeyRec;