Freescale Linux BSP review

[Dave Airlie]

On Tue, Dec 14, 2010 at 1:18 AM, Arnd Bergmann <arnd at arndb.de> wrote:
> On Monday 13 December 2010, Jammy Zhou wrote:
>> On Mon, Dec 13, 2010 at 4:45 AM, Linus Walleij <linus.walleij at linaro.org>wrote:
>>
>> > On 11 December 2010 22:41, Arnd Bergmann <arnd at arndb.de> wrote:
>> >
>> > * amd-gpu -- a single but huge driver for the GPU. As is normally the
>> >>             case with GPU drivers, we can expect long discussions
>> >>             before it will get considered for mainline
>> >>  4 patches
>> >>  98 files changed, 278321 insertions(+), 0 deletions(-)
>> >>
>> >
>> > Just out of curiosity, following the discussion between Dave Airlie
>> > and Codeaurora this summer re GPU driver shims.
>> >
>> > Is the AMD GPU exposing all functionality in its kernel driver or
>> > is there some userspace blob somewhere with lots of e.g. GL
>> > goodies?
>> >
>> All the functionality for the kernel driver of AMD GPU Z430/Z160 (now
>> belongs to Qualcom) is exposed. But we need accompanied userspace library to
>> call these functionality (buffer management, command submission, ...).
>
> Who owns these components? If it's closed source, the only options we
> have are lobbying for complete release of the specs for a reimplementation
> or reverse-engineering the drivers, which may at least get easier with
> a user space driver than it would be with a kernel driver.

Yeah even with the open kernel bits it makes no sense to upstream if
they never release the userspace,
since a GPU stack is a hw to sw interface stack you can't design a 3D
userspace driver without having
control of the kernel userspace interface, so setting an ABI in stone
for something that forces anyone
doing future development down a strict path is of no benefit.

Dave.