From: Aristeu Rozanski <arozansk@redhat.com>
Subject: [RHEL5.1 PATCH] v4l: use __GFP_DMA32 in videobuf_vm_nopage
Date: Tue, 8 May 2007 14:47:00 -0400
Bugzilla: 221478
Message-Id: <20070508184700.GA4215@redhat.com>
Changelog: [v4l] use __GFP_DMA32 in videobuf_vm_nopage


Using v4l applications in 64bit machines with gigs of memory currently
fails in RHEL5 because when the kernel allocates buffers to be visible
to the application by mmap() those pages may be located in addresses not
reachable by the capture cards. This patch ensures the allocated pages
will be visible by those cards using __GFP_DMA32 flag.

Upstream commit: 10329b962be782fa4fbebea9358063a4507d0c4d

Related BZ#s: BZ#221478

---

Fix bttv and friends on 64bit machines with lots of memory.

We have a DMA32 zone now, lets use it to make sure the card
can reach the memory we have allocated for the video frame
buffers.

Signed-off-by: Gerds Hoffmann <kraxel@suse.de>
---
 drivers/media/video/video-buf.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.18/drivers/media/video/video-buf.c
===================================================================
--- linux-2.6.18.orig/drivers/media/video/video-buf.c
+++ linux-2.6.18/drivers/media/video/video-buf.c
@@ -1224,7 +1224,7 @@ videobuf_vm_nopage(struct vm_area_struct
 		vaddr,vma->vm_start,vma->vm_end);
 	if (vaddr > vma->vm_end)
 		return NOPAGE_SIGBUS;
-	page = alloc_page(GFP_USER);
+	page = alloc_page(GFP_USER | __GFP_DMA32);
 	if (!page)
 		return NOPAGE_OOM;
 	clear_user_page(page_address(page), vaddr, page);