On 2015-10-30 00:16:43, Iago Toral wrote:
> On Wed, 2015-10-14 at 13:46 -0700, Jordan Justen wrote:
> > There is a discrepancy between the ARB_compute_shader specification,
> > and the OpenGL 4.3 and OpenGLES 3.1 specifications. With regards to
> > the indirect dispatch parameter, unsupported value errors should
> > return INVALID_VALUE according to the main specifications, whereas the
> > extension specification indicated INVALID_OPERATION should be
> > returned.
> >
> > Here we update the code to match the main specifications, and update
> > the citations use the main specification rather than the extension
> > specification.
> >
> > Signed-off-by: Jordan Justen <jordan.l.jus...@intel.com>
> > ---
> > Fixes ES31-CTS.compute_shader.api-indirect
> >
> > src/mesa/main/api_validate.c | 37 ++++++++++++++++++++++++++-----------
> > 1 file changed, 26 insertions(+), 11 deletions(-)
> >
> > diff --git a/src/mesa/main/api_validate.c b/src/mesa/main/api_validate.c
> > index a46c194..c286945 100644
> > --- a/src/mesa/main/api_validate.c
> > +++ b/src/mesa/main/api_validate.c
> > @@ -895,6 +895,11 @@ 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,
> > @@ -917,6 +922,12 @@ _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."
> > + */
> > if (num_groups[i] > ctx->Const.MaxComputeWorkGroupCount[i]) {
>
> This should be >= according to that spec quotation.
Wow. Good catch, except, I am fairly certain that this must be a spec
error. 'greater than' instead of 'greater than or equal' is more
consistent with the usage and other parts of the spec.
Unfortunately, this wording exists in the OpenGL 4.3 - 4.5 specs. What
a mess. :)
Here is some contradicting text from the DispatchCompute section of
4.3 spec:
"num groups x, num groups y and num groups z specify the number of
local work groups that will be dispatched in the X, Y and Z
dimensions, respectively."
"The maximum number of work groups that may be dispatched at one time
may be determined by calling GetIntegeri v with target set to
MAX_COMPUTE_WORK_GROUP_COUNT and index set to zero, one, or two,
representing the X, Y, and Z dimensions respectively."
So, it is saying that MAX_COMPUTE_WORK_GROUP_COUNT is the maximum
values. Thus being 'equal' to the max should be valid.
And, then in the DispatchComputeIndirect section of the 4.3 spec:
"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."
Note 'greater than' rather than 'greater than or equal'.
I'll ask the spec author about it, but in the meantime, I think I
should just skip adding this spec citation, or instead use the one
from above that starts with "The maximum number of " ...
What do you think?
>
> > _mesa_error(ctx, GL_INVALID_VALUE,
> > "glDispatchCompute(num_groups_%c)", 'x' + i);
> > @@ -937,24 +948,33 @@ valid_dispatch_indirect(struct gl_context *ctx,
> > if (!check_valid_to_compute(ctx, name))
> > return GL_FALSE;
> >
> > - /* From the ARB_compute_shader specification:
> > + /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
> > *
> > - * "An INVALID_OPERATION error is generated [...] if <indirect> is less
> > - * than zero or not a multiple of the size, in basic machine units, of
> > - * uint."
> > + * "An INVALID_VALUE error is generated if indirect is negative or is
> > not a
> > + * multiple of four."
> > + * Note that the OpenGLES 3.1 specification matches this, but this is
> > + * different than the extension specification which has a return of
> > + * INVALID_OPERATION instead.
>
> However, I read the following:
>
> "void DispatchComputeIndirect(intptr indirect);"
> (...)
> The error INVALID_VALUE is generated if <indirect> is less than zero or
> is not a multiple of four.(...)"
>
> and then again:
>
> "Errors:
> (...)
> INVALID_VALUE is generated by DispatchComputeIndirect if <indirect> is
> less than zero or not a multiple of four."
>
> From:
> https://www.opengl.org/registry/specs/ARB/compute_shader.txt
Hmm, so the ARB_compute_shader spec is inconsistent with itself. :(
How about I just drop the note that the ARB_compute_shader
contradicting the OpenGL spec? In other words:
- /* From the ARB_compute_shader specification:
+ /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
*
- * "An INVALID_OPERATION error is generated [...] if <indirect> is less
- * than zero or not a multiple of the size, in basic machine units, of
- * uint."
+ * "An INVALID_VALUE error is generated if indirect is negative or is not a
+ * multiple of four."
Thanks,
-Jordan
>
> > */
> > if ((GLintptr)indirect & (sizeof(GLuint) - 1)) {
> > - _mesa_error(ctx, GL_INVALID_OPERATION,
> > + _mesa_error(ctx, GL_INVALID_VALUE,
> > "%s(indirect is not aligned)", name);
> > return GL_FALSE;
> > }
> >
> > if ((GLintptr)indirect < 0) {
> > - _mesa_error(ctx, GL_INVALID_OPERATION,
> > + _mesa_error(ctx, GL_INVALID_VALUE,
> > "%s(indirect is less than zero)", name);
> > 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);
> > @@ -967,11 +987,6 @@ 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);
>
>
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