Fix X server crash when sis driver is used with EXA acceleration.

Source: http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/trusty/xserver-xorg-video-sis/trusty/revision/24/debian/patches/fix-exa-crash.diff

The patch was originally proposed by nihui:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-sis/+bug/1066464/comments/13

--- a/src/sis310_accel.c
+++ b/src/sis310_accel.c
@@ -1874,7 +1874,7 @@
 {
 	ScrnInfoPtr pScrn = xf86ScreenToScrn(pDst->drawable.pScreen);
 	SISPtr pSiS = SISPTR(pScrn);
-	unsigned char *dst = pDst->devPrivate.ptr;
+	unsigned char *dst = ((unsigned char *) pSiS->FbBase) + exaGetPixmapOffset(pDst);
 	int dst_pitch = exaGetPixmapPitch(pDst);
 
 	(pSiS->SyncAccel)(pScrn);
@@ -1882,7 +1882,7 @@
 	if(pDst->drawable.bitsPerPixel < 8)
 	   return FALSE;
 
-	dst += (x * pDst->drawable.bitsPerPixel / 8) + (y * src_pitch);
+	dst += (x * pDst->drawable.bitsPerPixel / 8) + (y * dst_pitch);
 	while(h--) {
 	   SiSMemCopyToVideoRam(pSiS, dst, (unsigned char *)src,
 				(w * pDst->drawable.bitsPerPixel / 8));
@@ -1953,7 +1953,7 @@
 {
 	ScrnInfoPtr pScrn = xf86ScreenToScrn(pSrc->drawable.pScreen);
 	SISPtr pSiS = SISPTR(pScrn);
-	unsigned char *src = pSrc->devPrivate.ptr;
+	unsigned char *src = ((unsigned char *) pSiS->FbBase) + exaGetPixmapOffset(pSrc);
 	int src_pitch = exaGetPixmapPitch(pSrc);
 	int size = src_pitch < dst_pitch ? src_pitch : dst_pitch;
 
@@ -1964,7 +1964,7 @@
 
 	src += (x * pSrc->drawable.bitsPerPixel / 8) + (y * src_pitch);
 	while(h--) {
-	   SiSMemCopyFromVideoRam(pSiS, (unsigned char *)dst, src, size);
+	   SiSMemCopyFromVideoRam(pSiS, (unsigned char *)dst, src, (w * pSrc->drawable.bitsPerPixel / 8));
 	   src += src_pitch;
 	   dst += dst_pitch;
 	}
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<div class='path'>path: <a href='/guix/log/?id=d1e77d69c1e04f402cec2e63553c001b1a4664ed'>root</a>/<a href='/guix/log/gnu?id=d1e77d69c1e04f402cec2e63553c001b1a4664ed'>gnu</a>/<a href='/guix/log/gnu/installer?id=d1e77d69c1e04f402cec2e63553c001b1a4664ed'>installer</a>/<a href='/guix/log/gnu/installer/aux-files?id=d1e77d69c1e04f402cec2e63553c001b1a4664ed'>aux-files</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/installer/aux-files?id=d1e77d69c1e04f402cec2e63553c001b1a4664ed&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-05-13 23:46:08 +0200'>2019-05-13</span></td><td><a href='/guix/commit/gnu/installer/aux-files?id=76269f6bc4200ef79aa80a8a6160ae269c2a36c9'>installer: Use 'glibc-supported-locales'.</a><span class='msg-avail'>...<span class='msg-tooltip'>The list of locales supported by glibc is now built from source.

* gnu/installer/locale.scm (locale-string-&gt;locale): Add optional
'codeset' parameter and honor it.
(supported-locales-&gt;locales): Rewrite to 'read' from SUPPORTED-LOCALES.
* gnu/installer.scm (compute-locale-step): Pass the result of
'glibc-supported-locales' instead of the "aux-files/SUPPORTED" file.
* gnu/installer/aux-files/SUPPORTED: Remove.
* gnu/local.mk (dist_installer_DATA): Remove it.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-01-17 14:04:20 +0100'>2019-01-17</span></td><td><a href='/guix/commit/gnu/installer/aux-files?id=d0f3a672dcbdfefd3556b6a21985ff0e35eed3be'>gnu: Add graphical installer support.</a><span class='msg-avail'>...<span class='msg-tooltip'>* configure.ac: Require that guile-newt is available.
* gnu/installer.scm: New file.
* gnu/installer/aux-files/logo.txt: New file.
* gnu/installer/build-installer.scm: New file.
* gnu/installer/connman.scm: New file.
* gnu/installer/keymap.scm: New file.
* gnu/installer/locale.scm: New file.
* gnu/installer/newt.scm: New file.
* gnu/installer/newt/ethernet.scm: New file.
* gnu/installer/newt/hostname.scm: New file.
* gnu/installer/newt/keymap.scm: New file.
* gnu/installer/newt/locale.scm: New file.
* gnu/installer/newt/menu.scm: New file.
* gnu/installer/newt/network.scm: New file.
* gnu/installer/newt/page.scm: New file.
* gnu/installer/newt/timezone.scm: New file.
* gnu/installer/newt/user.scm: New file.
* gnu/installer/newt/utils.scm: New file.
* gnu/installer/newt/welcome.scm: New file.
* gnu/installer/newt/wifi.scm: New file.
* gnu/installer/steps.scm: New file.
* gnu/installer/timezone.scm: New file.
* gnu/installer/utils.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add previous files.
* gnu/system.scm: Export %root-account.
* gnu/system/install.scm (%installation-services): Use kmscon instead of linux
VT for all tty.
(installation-os)[users]: Add the graphical installer as shell of the root
account.
[packages]: Add font related packages.
* po/guix/POTFILES.in: Add installer files.
</span></span></td><td>Mathieu Othacehe</td></tr>