On Thu, Feb 17, 2005 at 06:51:49PM +0100, Frank Buss wrote:
> I'm trying to use the pxafb driver on mach-pxa, but I can't mmap the
> framebuffer memory. I can access it from the driver, filling the entire
> screen, but when I access the pointer returned from mmap from a user space
> program, the following two things happens:
>
> - the vm_pgoff is ignored and I get the start of the internal buffer, which
> caused writing to the palette and DMA descriptors
>
> - when I change the location of the framebuffer to the start of the internal
> buffer, I can write to the screen, but only to the first 4 k; any write
> after this address is ignored, but no segfault is generated.
>
> Any ideas what I can do to find the reason? I don't think that it is a
> kernel bug, but perhaps a wrong configuration for my platform.
Please try this (and revert your changes):
===== arch/arm/mm/consistent.c 1.27 vs edited =====
--- 1.27/arch/arm/mm/consistent.c 2005-01-21 05:02:14 +00:00
+++ edited/arch/arm/mm/consistent.c 2005-02-17 18:11:50 +00:00
@@ -284,13 +284,15 @@
spin_unlock_irqrestore(&consistent_lock, flags);
if (c) {
+ unsigned long off = vma->vm_pgoff;
+
kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
- if (vma->vm_pgoff < kern_size &&
- user_size <= (kern_size - vma->vm_pgoff)) {
+ if (off < kern_size &&
+ user_size <= (kern_size - off)) {
vma->vm_flags |= VM_RESERVED;
ret = remap_pfn_range(vma, vma->vm_start,
- page_to_pfn(c->vm_pages),
+ page_to_pfn(c->vm_pages) + off,
user_size, vma->vm_page_prot);
}
}
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/
2.6 Serial core
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