[Intel-gfx] [PATCH 16/16] drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl

[Daniel Vetter]

On Sat, Dec 1, 2012 at 12:25 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Sat, 1 Dec 2012 00:06:43 +0100, Daniel Vetter <daniel at ffwll.ch> wrote:
>> Quick review:
>> - I don't like the internal byte offset we add/substract for relocations.
>>   mmap works on page boundaries, imo gpu mmap should do the same.
>
> However, the necessity is that I work on unaligned boundaries since I
> have no control over how the clients allocate the memory to be mapped,
> or which bytes within that memory are associated with a particular
> pixmap. The XShm API is such that not even the ShmSegment is passed down
> to the driver. That vies with the lack of explicit synchronisation
> points as being the worst elements of its design.

Well, I just want to move the page_offset computation from the kernel
to userspace. I know, this requires that you store that offset in
userspace somewhere, which requires a new field right next to the
existing u32 handle.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch