pmagb-b-fb: improve diagnostics

Add error messages to the probe call.

[adaplas]
On failure, return actual error value instead of -ENXIO.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/pmagb-b-fb.c

@@ -254,16 +254,23 @@ static int __init pmagbbfb_probe(struct device *dev)
 	struct pmagbbfb_par *par;
 	char freq0[12], freq1[12];
 	u32 vid_base;
+	int err;
 
 	info = framebuffer_alloc(sizeof(struct pmagbbfb_par), dev);
-	if (!info)
+	if (!info) {
+		printk(KERN_ERR "%s: Cannot allocate memory\n", dev->bus_id);
 		return -ENOMEM;
+	}
 
 	par = info->par;
 	dev_set_drvdata(dev, info);
 
-	if (fb_alloc_cmap(&info->cmap, 256, 0) < 0)
+	if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
+		printk(KERN_ERR "%s: Cannot allocate color map\n",
+		       dev->bus_id);
+		err = -ENOMEM;
 		goto err_alloc;
+	}
 
 	info->fbops = &pmagbbfb_ops;
 	info->fix = pmagbbfb_fix;
@@ -273,22 +280,31 @@ static int __init pmagbbfb_probe(struct device *dev)
 	/* Request the I/O MEM resource.  */
 	start = tdev->resource.start;
 	len = tdev->resource.end - start + 1;
-	if (!request_mem_region(start, len, dev->bus_id))
+	if (!request_mem_region(start, len, dev->bus_id)) {
+		printk(KERN_ERR "%s: Cannot reserve FB region\n", dev->bus_id);
+		err = -EBUSY;
 		goto err_cmap;
+	}
 
 	/* MMIO mapping setup.  */
 	info->fix.mmio_start = start;
 	par->mmio = ioremap_nocache(info->fix.mmio_start, info->fix.mmio_len);
-	if (!par->mmio)
+	if (!par->mmio) {
+		printk(KERN_ERR "%s: Cannot map MMIO\n", dev->bus_id);
+		err = -ENOMEM;
 		goto err_resource;
+	}
 	par->sfb = par->mmio + PMAGB_B_SFB;
 	par->dac = par->mmio + PMAGB_B_BT459;
 
 	/* Frame buffer mapping setup.  */
 	info->fix.smem_start = start + PMAGB_B_FBMEM;
 	par->smem = ioremap_nocache(info->fix.smem_start, info->fix.smem_len);
-	if (!par->smem)
+	if (!par->smem) {
+		printk(KERN_ERR "%s: Cannot map FB\n", dev->bus_id);
+		err = -ENOMEM;
 		goto err_mmio_map;
+	}
 	vid_base = sfb_read(par, SFB_REG_VID_BASE);
 	info->screen_base = (void __iomem *)par->smem + vid_base * 0x1000;
 	info->screen_size = info->fix.smem_len - 2 * vid_base * 0x1000;
@@ -297,8 +313,12 @@ static int __init pmagbbfb_probe(struct device *dev)
 	pmagbbfb_screen_setup(info);
 	pmagbbfb_osc_setup(info);
 
-	if (register_framebuffer(info) < 0)
+	err = register_framebuffer(info);
+	if (err < 0) {
+		printk(KERN_ERR "%s: Cannot register framebuffer\n",
+		       dev->bus_id);
 		goto err_smem_map;
+	}
 
 	get_device(dev);
 
@@ -330,7 +350,7 @@ err_cmap:
 
 err_alloc:
 	framebuffer_release(info);
-	return -ENXIO;
+	return err;
 }
 
 static int __exit pmagbbfb_remove(struct device *dev)