releases/2.6.33.15/drm-radeon-kms-fix-for-radeon-on-systems-4gb-without.patch

From 62fff811d73095bd95579d72f558f03c78f7914a Mon Sep 17 00:00:00 2001
From: Daniel Haid <d.haid@gogi.tv>
Date: Wed, 8 Jun 2011 20:04:45 +1000
Subject: drm/radeon/kms: fix for radeon on systems >4GB without
 hardware iommu

From: Daniel Haid <d.haid@gogi.tv>

commit 62fff811d73095bd95579d72f558f03c78f7914a upstream.

On my x86_64 system with >4GB of ram and swiotlb instead of
a hardware iommu (because I have a VIA chipset), the call
to pci_set_dma_mask (see below) with 40bits returns an error.

But it seems that the radeon driver is designed to have
need_dma32 = true exactly if pci_set_dma_mask is called
with 32 bits and false if it is called with 40 bits.

I have read somewhere that the default are 32 bits. So if the
call fails I suppose that need_dma32 should be set to true.

And indeed the patch fixes the problem I have had before
and which I had described here:
http://choon.net/forum/read.php?21,106131,115940

Acked-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/gpu/drm/radeon/radeon_device.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -682,6 +682,7 @@ int radeon_device_init(struct radeon_dev
 	dma_bits = rdev->need_dma32 ? 32 : 40;
 	r = pci_set_dma_mask(rdev->pdev, DMA_BIT_MASK(dma_bits));
 	if (r) {
+		rdev->need_dma32 = true;
 		printk(KERN_WARNING "radeon: No suitable DMA available.\n");
 	}