From 8aff8c658925f0c7522555ff5907632bcafe4554 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Mon, 13 May 2019 15:41:54 +0200
Subject: gpu_sim_check: Succeed if GPU not available

On recent OSes, OpenCL (the API) is always available, but a GPU device
not always.  Therefore, this test will always be built, and shouldn't
fail just because a GPU isn't present.
---
 src/cl-utils.c        | 38 ++++++++++++++++++++++++++++++++++++--
 src/cl-utils.h        | 11 +++++++++--
 tests/gpu_sim_check.c | 10 ++++++++--
 3 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/src/cl-utils.c b/src/cl-utils.c
index fee2b53e..7c069ed1 100644
--- a/src/cl-utils.c
+++ b/src/cl-utils.c
@@ -3,11 +3,11 @@
  *
  * OpenCL utility functions
  *
- * Copyright © 2012-2018 Deutsches Elektronen-Synchrotron DESY,
+ * Copyright © 2012-2019 Deutsches Elektronen-Synchrotron DESY,
  *                       a research centre of the Helmholtz Association.
  *
  * Authors:
- *   2010-2018 Thomas White <taw@physics.org>
+ *   2010-2019 Thomas White <taw@physics.org>
  *
  * This file is part of CrystFEL.
  *
@@ -43,6 +43,40 @@
 #include "utils.h"
 
 
+/* Return 1 if a GPU device is present, 0 if not, 2 on error. */
+int have_gpu_device()
+{
+	cl_uint nplat;
+	cl_platform_id platforms[8];
+	cl_context_properties prop[3];
+	cl_int err;
+	int i;
+
+	err = clGetPlatformIDs(8, platforms, &nplat);
+	if ( err != CL_SUCCESS ) return 2;
+	if ( nplat == 0 ) return 0;
+
+	/* Find a GPU platform in the list */
+	for ( i=0; i<nplat; i++ ) {
+
+		prop[0] = CL_CONTEXT_PLATFORM;
+		prop[1] = (cl_context_properties)platforms[i];
+		prop[2] = 0;
+
+		clCreateContextFromType(prop, CL_DEVICE_TYPE_GPU,
+		                        NULL, NULL, &err);
+
+		if ( err != CL_SUCCESS ) {
+			if ( err != CL_DEVICE_NOT_FOUND ) return 2;
+		} else {
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+
 const char *clError(cl_int err)
 {
 	switch ( err ) {
diff --git a/src/cl-utils.h b/src/cl-utils.h
index fcaf1380..92bea562 100644
--- a/src/cl-utils.h
+++ b/src/cl-utils.h
@@ -3,11 +3,11 @@
  *
  * OpenCL utility functions
  *
- * Copyright © 2012-2018 Deutsches Elektronen-Synchrotron DESY,
+ * Copyright © 2012-2019 Deutsches Elektronen-Synchrotron DESY,
  *                       a research centre of the Helmholtz Association.
  *
  * Authors:
- *   2010-2018 Thomas White <taw@physics.org>
+ *   2010-2019 Thomas White <taw@physics.org>
  *
  * This file is part of CrystFEL.
  *
@@ -34,6 +34,13 @@
 #endif
 
 
+#ifdef HAVE_CL_CL_H
+#include <CL/cl.h>
+#else
+#include <cl.h>
+#endif
+
+extern int have_gpu_device(void);
 extern const char *clError(cl_int err);
 extern cl_device_id get_cl_dev(cl_context ctx, int n);
 extern cl_program load_program_from_string(const char *source_in, size_t len,
diff --git a/tests/gpu_sim_check.c b/tests/gpu_sim_check.c
index aee7a068..e42bc68b 100644
--- a/tests/gpu_sim_check.c
+++ b/tests/gpu_sim_check.c
@@ -3,11 +3,11 @@
  *
  * Check that GPU simulation agrees with CPU version
  *
- * Copyright © 2012-2015 Deutsches Elektronen-Synchrotron DESY,
+ * Copyright © 2012-2019 Deutsches Elektronen-Synchrotron DESY,
  *                       a research centre of the Helmholtz Association.
  *
  * Authors:
- *   2012-2015 Thomas White <taw@physics.org>
+ *   2012-2019 Thomas White <taw@physics.org>
  *
  * This file is part of CrystFEL.
  *
@@ -42,6 +42,7 @@
 
 #include "../src/diffraction.h"
 #include "../src/diffraction-gpu.h"
+#include "../src/cl-utils.h"
 #include <detector.h>
 #include <utils.h>
 #include <symmetry.h>
@@ -90,6 +91,11 @@ int main(int argc, char *argv[])
 	SymOpList *sym;
 	gsl_rng *rng;
 
+	if ( have_gpu_device() == 0 ) {
+		ERROR("No GPU device found - skipping test.\n");
+		return 0;
+	}
+
 	rng = gsl_rng_alloc(gsl_rng_mt19937);
 
 	gctx = setup_gpu(1, NULL, NULL, NULL, 0);
-- 
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