1 files changed, 73 insertions, 1 deletions

diff --git a/drivers/video/nvidia/nvidia.c b/drivers/video/nvidia/nvidia.c
index c6afafcfc24b..610575319444 100644
--- a/drivers/video/nvidia/nvidia.c
+++ b/drivers/video/nvidia/nvidia.c
@@ -949,8 +949,80 @@ static int nvidiafb_blank(int blank, struct fb_info *info)
         return 0;
 }
 
+/*
+ * Because the VGA registers are not mapped linearly in its MMIO space,
+ * restrict VGA register saving and restore to x86 only, where legacy VGA IO
+ * access is legal. Consequently, we must also check if the device is the
+ * primary display.
+ */
+#ifdef CONFIG_X86
+static void save_vga_x86(struct nvidia_par *par)
+{
+        struct resource *res= &par->pci_dev->resource[PCI_ROM_RESOURCE];
+
+        if (res && res->flags & IORESOURCE_ROM_SHADOW) {
+                memset(&par->vgastate, 0, sizeof(par->vgastate));
+                par->vgastate.flags = VGA_SAVE_MODE | VGA_SAVE_FONTS |
+                        VGA_SAVE_CMAP;
+                save_vga(&par->vgastate);
+        }
+}
+
+static void restore_vga_x86(struct nvidia_par *par)
+{
+        struct resource *res= &par->pci_dev->resource[PCI_ROM_RESOURCE];
+
+        if (res && res->flags & IORESOURCE_ROM_SHADOW)
+                restore_vga(&par->vgastate);
+}
+#else
+#define save_vga_x86(x) do {} while (0)
+#define restore_vga_x86(x) do {} while (0)
+#endif /* X86 */
+
+static int nvidiafb_open(struct fb_info *info, int user)
+{
+        struct nvidia_par *par = info->par;
+
+        mutex_lock(&par->open_lock);
+
+        if (!par->open_count) {
+                save_vga_x86(par);
+                nvidia_save_vga(par, &par->initial_state);
+        }
+
+        par->open_count++;
+        mutex_unlock(&par->open_lock);
+        return 0;
+}
+
+static int nvidiafb_release(struct fb_info *info, int user)
+{
+        struct nvidia_par *par = info->par;
+        int err = 0;
+
+        mutex_lock(&par->open_lock);
+
+        if (!par->open_count) {
+                err = -EINVAL;
+                goto done;
+        }
+
+        if (par->open_count == 1) {
+                nvidia_write_regs(par, &par->initial_state);
+                restore_vga_x86(par);
+        }
+
+        par->open_count--;
+done:
+        mutex_unlock(&par->open_lock);
+        return 0;
+}
+
 static struct fb_ops nvidia_fb_ops = {
         .owner          = THIS_MODULE,
+        .fb_open        = nvidiafb_open,
+        .fb_release     = nvidiafb_release,
         .fb_check_var   = nvidiafb_check_var,
         .fb_set_par     = nvidiafb_set_par,
         .fb_setcolreg   = nvidiafb_setcolreg,
@@ -1208,7 +1280,7 @@ static int __devinit nvidiafb_probe(struct pci_dev *pd,
 
         par = info->par;
         par->pci_dev = pd;
-
+        mutex_init(&par->open_lock);
         info->pixmap.addr = kzalloc(8 * 1024, GFP_KERNEL);
 
         if (info->pixmap.addr == NULL)