[Mesa-dev] [PATCH 2/3] gallium: define the behavior of PIPE_USAGE_* flags properly

[Marek Olšák]

On Wed, Feb 5, 2014 at 10:00 PM, Brian Paul <brianp at vmware.com> wrote:
> On 02/04/2014 04:26 PM, Marek Olšák wrote:
>>
>> From: Marek Olšák <marek.olsak at amd.com>
>>
>> STATIC will be removed in the following commit.
>> ---
>>   src/gallium/docs/source/screen.rst   | 18 ++++++++++++------
>>   src/gallium/include/pipe/p_defines.h | 13 +++++++------
>>   2 files changed, 19 insertions(+), 12 deletions(-)
>>
>> diff --git a/src/gallium/docs/source/screen.rst
>> b/src/gallium/docs/source/screen.rst
>> index c26f98c..5932e3b 100644
>> --- a/src/gallium/docs/source/screen.rst
>> +++ b/src/gallium/docs/source/screen.rst
>> @@ -343,12 +343,18 @@ PIPE_USAGE_*
>>   ^^^^^^^^^^^^
>>
>>   The PIPE_USAGE enums are hints about the expected usage pattern of a
>> resource.
>> -
>> -* ``PIPE_USAGE_DEFAULT``: Expect many uploads to the resource, intermixed
>> with draws.
>> -* ``PIPE_USAGE_DYNAMIC``: Expect many uploads to the resource, intermixed
>> with draws.
>> -* ``PIPE_USAGE_STATIC``: Same as immutable (?)
>> -* ``PIPE_USAGE_IMMUTABLE``: Resource will not be changed after first
>> upload.
>> -* ``PIPE_USAGE_STREAM``: Upload will be followed by draw, followed by
>> upload, ...
>> +Note that drivers must always support read and write CPU access at any
>> time
>> +no matter which hint they got.
>> +
>> +* ``PIPE_USAGE_DEFAULT``: Optimized for fast GPU access.
>> +* ``PIPE_USAGE_IMMUTABLE``: Optimized for fast GPU access and the
>> resource is
>> +  not expected to be mapped after the first upload.
>
>
> How about "mapped or changed"?  For example, an immutable resource probably
> shouldn't be the dest of a blit.

Isn't it too strict? Who would want to have such a strict flag?

Marek