1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/video/sis/sis_main.c b/drivers/video/sis/sis_main.c
index b52f8e4ef1fd..3dde12b0ab06 100644
--- a/drivers/video/sis/sis_main.c
+++ b/drivers/video/sis/sis_main.c
@@ -4181,6 +4181,9 @@ static void __devinit
 sisfb_post_map_vram(struct sis_video_info *ivideo, unsigned int *mapsize,
                         unsigned int min)
 {
+        if (*mapsize < (min << 20))
+                return;
+
         ivideo->video_vbase = ioremap(ivideo->video_base, (*mapsize));
 
         if(!ivideo->video_vbase) {
@@ -4514,7 +4517,7 @@ sisfb_post_sis300(struct pci_dev *pdev)
         } else {
 #endif
                 /* Need to map max FB size for finding out about RAM size */
-                mapsize = 64 << 20;
+                mapsize = ivideo->video_size;
                 sisfb_post_map_vram(ivideo, &mapsize, 4);
 
                 if(ivideo->video_vbase) {
@@ -4680,7 +4683,7 @@ sisfb_post_xgi_ramsize(struct sis_video_info *ivideo)
         orSISIDXREG(SISSR, 0x20, (0x80 | 0x04));
 
         /* Need to map max FB size for finding out about RAM size */
-        mapsize = 256 << 20;
+        mapsize = ivideo->video_size;
         sisfb_post_map_vram(ivideo, &mapsize, 32);
 
         if(!ivideo->video_vbase) {
@@ -5936,6 +5939,7 @@ sisfb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
         }
 
         ivideo->video_base = pci_resource_start(pdev, 0);
+        ivideo->video_size = pci_resource_len(pdev, 0);
         ivideo->mmio_base  = pci_resource_start(pdev, 1);
         ivideo->mmio_size  = pci_resource_len(pdev, 1);
         ivideo->SiS_Pr.RelIO = pci_resource_start(pdev, 2) + 0x30;