On 2015-11-02 00:35:36, Jordan Justen wrote:
> Note: The OpenGL 4.3 - 4.5 specification language for DispatchCompute
> appears to have an error regarding the max allowed values. When adding
> the specification citation, we note why the code does not match the
> specification language.
>
> v2:
> * Updates based on review from Iago
>
> Signed-off-by: Jordan Justen <jordan.l.jus...@intel.com>
> Cc: Iago Toral Quiroga <ito...@igalia.com>
> Cc: Marta Lofstedt <marta.lofst...@intel.com>
> ---
> src/mesa/main/api_validate.c | 34 +++++++++++++++++++++++++++++-----
> 1 file changed, 29 insertions(+), 5 deletions(-)
>
> diff --git a/src/mesa/main/api_validate.c b/src/mesa/main/api_validate.c
> index a3ee8c0..a490189 100644
> --- a/src/mesa/main/api_validate.c
> +++ b/src/mesa/main/api_validate.c
> @@ -918,6 +918,11 @@ check_valid_to_compute(struct gl_context *ctx, const
> char *function)
> return false;
> }
>
> + /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
> + *
> + * "An INVALID_OPERATION error is generated if there is no active program
> + * for the compute shader stage."
> + */
> prog = ctx->_Shader->CurrentProgram[MESA_SHADER_COMPUTE];
> if (prog == NULL || prog->_LinkedShaders[MESA_SHADER_COMPUTE] == NULL) {
> _mesa_error(ctx, GL_INVALID_OPERATION,
> @@ -940,6 +945,24 @@ _mesa_validate_DispatchCompute(struct gl_context *ctx,
> return GL_FALSE;
>
> for (i = 0; i < 3; i++) {
> + /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
> + *
> + * "An INVALID_VALUE error is generated if any of num_groups_x,
> + * num_groups_y and num_groups_z are greater than or equal to the
> + * maximum work group count for the corresponding dimension."
> + *
> + * However, the "or equal to" portions appears to be a specification
> + * bug. In all other areas, the specification appears to indicate that
> + * the number of workgroups can match the MAX_COMPUTE_WORK_GROUP_COUNT
> + * value. For example, under DispatchComputeIndirect:
> + *
> + * "If any of num_groups_x, num_groups_y or num_groups_z is greater
> than
> + * the value of MAX_COMPUTE_WORK_GROUP_COUNT for the corresponding
> + * dimension then the results are undefined."
> + *
> + * Additionally, the OpenGLES 3.1 specification does not contain "or
> + * equal to" as an error condition.
I did get confirmation from the extension spec author that this
appears to be a bug in the OpenGL 4.3 - 4.5 specs, and I filed an
OpenGL spec bug.
-Jordan
> + */
> if (num_groups[i] > ctx->Const.MaxComputeWorkGroupCount[i]) {
> _mesa_error(ctx, GL_INVALID_VALUE,
> "glDispatchCompute(num_groups_%c)", 'x' + i);
> @@ -977,6 +1000,12 @@ valid_dispatch_indirect(struct gl_context *ctx,
> return GL_FALSE;
> }
>
> + /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
> + *
> + * "An INVALID_OPERATION error is generated if no buffer is bound to the
> + * DRAW_INDIRECT_BUFFER binding, or if the command would source data
> + * beyond the end of the buffer object."
> + */
> if (!_mesa_is_bufferobj(ctx->DispatchIndirectBuffer)) {
> _mesa_error(ctx, GL_INVALID_OPERATION,
> "%s: no buffer bound to DISPATCH_INDIRECT_BUFFER", name);
> @@ -989,11 +1018,6 @@ valid_dispatch_indirect(struct gl_context *ctx,
> return GL_FALSE;
> }
>
> - /* From the ARB_compute_shader specification:
> - *
> - * "An INVALID_OPERATION error is generated if this command sources data
> - * beyond the end of the buffer object [...]"
> - */
> if (ctx->DispatchIndirectBuffer->Size < end) {
> _mesa_error(ctx, GL_INVALID_OPERATION,
> "%s(DISPATCH_INDIRECT_BUFFER too small)", name);
> --
> 2.6.2
>
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