[Mesa-dev] [RFC 7/7] radeon: remove screen ref counting

[Rob Herring]

On Mon, Jun 20, 2016 at 8:31 AM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> On 17.06.2016 21:05, Rob Herring wrote:
>>
>> On Fri, Jun 17, 2016 at 1:45 PM, Emil Velikov <emil.l.velikov at gmail.com>
>> wrote:
>>>
>>> On 17 June 2016 at 18:45, Rob Herring <robh at kernel.org> wrote:
>>>>
>>>> Now that the pipe-loader is reference counting the screen creation, it
>>>> is unnecessary to do in it the winsys/driver.
>>
>>
>> [...]
>>
>>>> -static unsigned hash_dev(void *key)
>>>> -{
>>>> -#if defined(PIPE_ARCH_X86_64)
>>>> -   return pointer_to_intptr(key) ^ (pointer_to_intptr(key) >> 32);
>>>> -#else
>>>> -   return pointer_to_intptr(key);
>>>> -#endif
>>>> -}
>>>> -
>>>
>>> As you can see above the hashing algo is different for AMDGPU. Not
>>> familiar with the story behind any of this, so hopefully the AMD folk
>>> will give you some insights.
>>
>>
>> They are also hashing the fd in libdrm amdgpu_device_initialize(), so
>> I thought this was redundant (unless you have an old libdrm).
>
>
> Correct. The idea is that there may be non-Mesa users of libdrm_amdgpu (in
> particular, the amdgpu-pro stack).
>
> The hashing in libdrm is different as well, though, and apparently on
> purpose, see commit c68d58aa14b7f of libdrm. This might mean the series
> doesn't work as is. Christian or Marek might know more.

Okay, so the screen needs to be re-used across card and render nodes.
Seems like other drivers could need that behavior as well and I should
use the libdrm version.

Rob