gma500: Fix mmap frambuffer

commit 1278f7de7fa5606ed513a5271f7fb63910ef1b8b upstream.

It cannot map correctly if page fault begins from a intermediate address.

[The driver prefaults the mapping, so we need to work from the correct
 base address not the faulting address otherwise the map appears offset by
 the fault offset]

Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index be616735ec918502238df831ad59510513358996..515449374e9f0aad2a10c2dbec989e8c07599a7a 100644 (file)
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -158,7 +158,7 @@ static int psbfb_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
        unsigned long phys_addr = (unsigned long)dev_priv->stolen_base;
 
        page_num = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
-       address = (unsigned long)vmf->virtual_address;
+       address = (unsigned long)vmf->virtual_address - (vmf->pgoff << PAGE_SHIFT);
 
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);