[PATCH 1/2] intel: Add support for overriding the PCI ID via an environment variable

[kenneth at whitecape.org (Kenneth Graunke)]

For example:

    export INTEL_DEVID_OVERRIDE=0x162

If this variable is set, don't actually submit the batchbuffer to the
GPU, it probably contains commands for the wrong generation of hardware.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 intel/intel_bufmgr_gem.c |   43 ++++++++++++++++++++++++++++++++++---------
 1 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index 0f33b71..fcb4764 100644
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -1788,7 +1788,8 @@ drm_intel_gem_bo_mrb_exec2(drm_intel_bo *bo, int used,
 {
 	drm_intel_bufmgr_gem *bufmgr_gem = (drm_intel_bufmgr_gem *)bo->bufmgr;
 	struct drm_i915_gem_execbuffer2 execbuf;
-	int ret, i;
+	int ret = 0;
+	int i;
 
 	switch (flags & 0x7) {
 	default:
@@ -1828,6 +1829,9 @@ drm_intel_gem_bo_mrb_exec2(drm_intel_bo *bo, int used,
 	execbuf.rsvd1 = 0;
 	execbuf.rsvd2 = 0;
 
+	if (getenv("INTEL_DEVID_OVERRIDE"))
+		goto skip_execution;
+
 	ret = drmIoctl(bufmgr_gem->fd,
 		       DRM_IOCTL_I915_GEM_EXECBUFFER2,
 		       &execbuf);
@@ -1845,6 +1849,7 @@ drm_intel_gem_bo_mrb_exec2(drm_intel_bo *bo, int used,
 	}
 	drm_intel_update_buffer_offsets2(bufmgr_gem);
 
+skip_execution:
 	if (bufmgr_gem->bufmgr.debug)
 		drm_intel_gem_dump_validation_list(bufmgr_gem);
 
@@ -2315,6 +2320,33 @@ drm_intel_bufmgr_gem_set_vma_cache_size(drm_intel_bufmgr *bufmgr, int limit)
 }
 
 /**
+ * Get the PCI ID for the device.  This can be overridden by setting the
+ * INTEL_DEVID_OVERRIDE environment variable to the desired ID.
+ */
+static int
+get_pci_device_id(drm_intel_bufmgr_gem *bufmgr_gem)
+{
+	char *devid_override;
+	int devid;
+	int ret;
+	drm_i915_getparam_t gp;
+
+	devid_override = getenv("INTEL_DEVID_OVERRIDE");
+	if (devid_override)
+		return strtod(devid_override, NULL);
+
+	VG_CLEAR(gp);
+	gp.param = I915_PARAM_CHIPSET_ID;
+	gp.value = &devid;
+	ret = drmIoctl(bufmgr_gem->fd, DRM_IOCTL_I915_GETPARAM, &gp);
+	if (ret) {
+		fprintf(stderr, "get chip id failed: %d [%d]\n", ret, errno);
+		fprintf(stderr, "param: %d, val: %d\n", gp.param, *gp.value);
+	}
+	return devid;
+}
+
+/**
  * Initializes the GEM buffer manager, which uses the kernel to allocate, map,
  * and manage map buffer objections.
  *
@@ -2356,14 +2388,7 @@ drm_intel_bufmgr_gem_init(int fd, int batch_size)
 			(int)bufmgr_gem->gtt_size / 1024);
 	}
 
-	VG_CLEAR(gp);
-	gp.param = I915_PARAM_CHIPSET_ID;
-	gp.value = &bufmgr_gem->pci_device;
-	ret = drmIoctl(bufmgr_gem->fd, DRM_IOCTL_I915_GETPARAM, &gp);
-	if (ret) {
-		fprintf(stderr, "get chip id failed: %d [%d]\n", ret, errno);
-		fprintf(stderr, "param: %d, val: %d\n", gp.param, *gp.value);
-	}
+	bufmgr_gem->pci_device = get_pci_device_id(bufmgr_gem);
 
 	if (IS_GEN2(bufmgr_gem->pci_device))
 		bufmgr_gem->gen = 2;
-- 
1.7.7.6