From 2be405b4145842cd1d2a1df11eeb3d49401fadf2 Mon Sep 17 00:00:00 2001
From: Alberto Milone <alberto.milone@canonical.com>
Date: Mon, 10 Mar 2014 14:53:04 +0100
Subject: [PATCH 1/1] Register VT switch requirements

Make sure to call pm_vt_switch_{required,unregister}(), so that
the kernel knows that the driver requires a vt switch at
suspend/resume time.

This resolves a corruption issue on resume from S3 (LP: #1210077).

Thanks to NVIDIA for providing the patch.
---
 Makefile    |    3 ++-
 conftest.sh |   23 +++++++++++++++++++++++
 nv.c        |    6 ++++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index ca5399d..8b0c77d 100644
--- a/Makefile
+++ b/Makefile
@@ -130,7 +130,8 @@ COMPILE_TESTS = \
 	drm_available \
 	proc_create_data \
 	pde_data \
-	proc_remove
+	proc_remove \
+	pm_vt_switch_required
 
 #
 # CFLAGS dependent on the type of builds (e.g. single/muliple module, debug)
diff --git a/conftest.sh b/conftest.sh
index fbaaff6..9b297ff 100755
--- a/conftest.sh
+++ b/conftest.sh
@@ -1829,6 +1829,29 @@ compile_test() {
             fi
         ;;
 
+        pm_vt_switch_required)
+            #
+            # Determine if the pm_vt_switch_required() function is present.
+            #
+            echo "$CONFTEST_PREAMBLE
+            #include <linux/pm.h>
+            void conftest_pm_vt_switch_required(void) {
+                pm_vt_switch_required();
+            }" > conftest$$.c
+
+            $CC $CFLAGS -c conftest$$.c > /dev/null 2>&1
+            rm -f conftest$$.c
+
+            if [ -f conftest$$.o ]; then
+                rm -f conftest$$.o
+                echo "#undef NV_PM_VT_SWITCH_REQUIRED_PRESENT" | append_conftest "functions"
+                return
+            else
+                echo "#define NV_PM_VT_SWITCH_REQUIRED_PRESENT" | append_conftest "functions"
+                return
+            fi
+        ;;
+
     esac
 }
 
diff --git a/nv.c b/nv.c
index 343332c..b9d889c 100644
--- a/nv.c
+++ b/nv.c
@@ -1066,6 +1066,9 @@ int __init nvidia_init_module(void)
 #else
         nvl->nv_state.flags &= ~NV_FLAG_S4_AVAILABLE;
 #endif
+#if defined(NV_PM_VT_SWITCH_REQUIRED_PRESENT)
+        pm_vt_switch_required(&nvl->dev->dev, NV_TRUE);
+#endif
     }
     return 0;
 
@@ -1169,6 +1172,9 @@ void __exit nvidia_exit_module(void)
 
         if ((dev = nvl->dev) != NULL)
         {
+#if defined(NV_PM_VT_SWITCH_REQUIRED_PRESENT)
+            pm_vt_switch_unregister(&dev->dev);
+#endif
             if (NV_IS_GVI_DEVICE(nv))
             {
                 NV_TASKQUEUE_FLUSH();
-- 
1.7.9.5