[Beignet] [PATCH] Make __local on Haswell an error, instead of silently doing nothing

[Rebecca N. Palmer]

Given that really fixing shared local memory on Haswell is likely
to take some time, at least make it an explicit error that points
the user to the kernel patch, instead of returning "success"
without actually doing the computation.

As I can't find an error code to check for this problem (if there
was one I'd guess at drm_intel_gem_bo_context_exec(), but we
already check that), this unconditionally rejects __local use on
Haswell, so you'd have to undo it to use the kernel patch.
Is there a better way to check this? or should we make it a warning
instead of an error (omit "return CL_OUT_OF_RESOURCES;")?

Also, improve the drm_intel_gem_bo_context_exec() error message.

Warning: not properly tested, as I don't have the affected hardware;
if you prefer not to apply this to development trunk, I'd still
appreciate confirmation of whether it works.

Signed-off-by: Rebecca Palmer <rebecca_palmer at zoho.com>

--- a/src/cl_command_queue_gen7.c
+++ b/src/cl_command_queue_gen7.c
@@ -351,6 +351,10 @@ cl_command_queue_ND_range_gen7(cl_comman
    /* Curbe step 1: fill the constant urb buffer data shared by all threads */
    if (ker->curbe) {
      kernel.slm_sz = cl_curbe_fill(ker, work_dim, global_wk_off, global_wk_sz, local_wk_sz, thread_n);
+    if (kernel.slm_sz > 0 && cl_driver_get_ver(ctx->drv) == 75){
+      fprintf(stderr, "Beignet: Shared local memory does not work on Haswell, see https://01.org/zh/beignet/downloads/linux-kernel-patch-hsw-support\n");
+      return CL_OUT_OF_RESOURCES;
+    }
      if (kernel.slm_sz > ker->program->ctx->device->local_mem_size) {
        fprintf(stderr, "Beignet: Out of shared local memory %d.\n", kernel.slm_sz);
        return CL_OUT_OF_RESOURCES;
--- a/src/intel/intel_batchbuffer.c
+++ b/src/intel/intel_batchbuffer.c
@@ -135,6 +135,10 @@ intel_batchbuffer_flush(intel_batchbuffe
    }
    if (drm_intel_gem_bo_context_exec(batch->buffer, batch->intel->ctx, used, flag) < 0) {
      fprintf(stderr, "drm_intel_gem_bo_context_exec() failed: %s\n", strerror(errno));
+    if (errno == EINVAL && IS_GEN75(batch->intel->device_id)) {
+      fprintf(stderr, "This is a known bug on Haswell systems, see http://www.freedesktop.org/wiki/Software/Beignet/\n"
+                "'sudo echo 0 > /sys/module/i915/parameters/enable_cmd_parser' usually helps\n");
+    }
      err = -1;
    }