drm/ast: Try to use MMIO registers when PIO isn't supported

[cascardo/linux.git] / drivers / gpu / drm / ast / ast_main.c

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index a2cc6be..c2ff793 100644 (file)
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -359,10 +359,24 @@ int ast_driver_load(struct drm_device *dev, unsigned long flags)
                ret = -EIO;
                goto out_free;
        }
-       ast->ioregs = pci_iomap(dev->pdev, 2, 0);
+
+       /*
+        * If we don't have IO space at all, use MMIO now and
+        * assume the chip has MMIO enabled by default (rev 0x20
+        * and higher).
+        */
+       if (!(pci_resource_flags(dev->pdev, 2) & IORESOURCE_IO)) {
+               DRM_INFO("platform has no IO space, trying MMIO\n");
+               ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
+       }
+
+       /* "map" IO regs if the above hasn't done so already */
        if (!ast->ioregs) {
-               ret = -EIO;
-               goto out_free;
+               ast->ioregs = pci_iomap(dev->pdev, 2, 0);
+               if (!ast->ioregs) {
+                       ret = -EIO;
+                       goto out_free;
+               }
        }
 
        ast_detect_chip(dev);