staging: xgifb: fix LVDS LCD resolution data setup

If the driver fails to get LVDS LCD data from the firmware, it falls
back to using driver's hardcoded values. However, this is done too
early in the probe. The selected video mode index is not yet known,
and also in some cases it could be defaulting to -1 resulting in a read
outside the array. Fix this by moving the array lookup after the video
mode validation.
Signed-off-by: NAaro Koskinen <aaro.koskinen@iki.fi>
Reported-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/xgifb/XGI_main_26.c

@@ -2021,6 +2021,7 @@ static int __devinit xgifb_probe(struct pci_dev *pdev,
 	u8 reg, reg1;
 	u8 CR48, CR38;
 	int ret;
+	bool xgi21_drvlcdcaplist = false;
 
 	memset(&XGIhw_ext, 0, sizeof(struct xgi_hw_device_info));
 	fb_info = framebuffer_alloc(sizeof(struct fb_info), &pdev->dev);
@@ -2174,15 +2175,8 @@ static int __devinit xgifb_probe(struct pci_dev *pdev,
 		CR38 = xgifb_reg_get(XGICR, 0x38);
 		if ((CR38&0xE0) == 0xC0) {
 			xgi_video_info.disp_state = DISPTYPE_LCD;
-			if (!XGIfb_GetXG21LVDSData()) {
-				int m;
-				for (m = 0; m < sizeof(XGI21_LCDCapList)/sizeof(struct XGI21_LVDSCapStruct); m++) {
-					if ((XGI21_LCDCapList[m].LVDSHDE == XGIbios_mode[xgifb_mode_idx].xres) &&
-					    (XGI21_LCDCapList[m].LVDSVDE == XGIbios_mode[xgifb_mode_idx].yres)) {
-						xgifb_reg_set(XGI_Pr.P3d4, 0x36, m);
-					}
-				}
-			}
+			if (!XGIfb_GetXG21LVDSData())
+				xgi21_drvlcdcaplist = true;
 		} else if ((CR38&0xE0) == 0x60) {
 			xgi_video_info.hasVB = HASVB_CHRONTEL;
 		} else {
@@ -2334,6 +2328,19 @@ static int __devinit xgifb_probe(struct pci_dev *pdev,
 		}
 	}
 
+	if (xgi21_drvlcdcaplist) {
+		int m;
+
+		for (m = 0; m < ARRAY_SIZE(XGI21_LCDCapList); m++)
+			if ((XGI21_LCDCapList[m].LVDSHDE ==
+				XGIbios_mode[xgifb_mode_idx].xres) &&
+			    (XGI21_LCDCapList[m].LVDSVDE ==
+				XGIbios_mode[xgifb_mode_idx].yres)) {
+				xgifb_reg_set(XGI_Pr.P3d4, 0x36, m);
+				break;
+			}
+	}
+
 	XGIfb_mode_no = XGIbios_mode[xgifb_mode_idx].mode_no;
 
 	/* yilin set default refresh rate */