drm/i915: Disable the BLT on pre-production SNB hardware
It never quite worked despite the numerous workarounds, yet I still see
people trying to use this hardware and filing bug reports. As we no
longer even try to implement the workarounds, since 6a233c78878
(drm/i915/ringbuffer: kill snb blt workaround), simply disable the ring.
v2: Add a message to inform the user about the limited capabilities of
their pre-production hardware.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 0fdb3d2..89d62f6 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3726,6 +3726,22 @@
}
}
+static bool
+intel_enable_blt(struct drm_device *dev)
+{
+ if (!HAS_BLT(dev))
+ return false;
+
+ /* The blitter was dysfunctional on early prototypes */
+ if (IS_GEN6(dev) && dev->pdev->revision < 8) {
+ DRM_INFO("BLT not supported on this pre-production hardware;"
+ " graphics performance will be degraded.\n");
+ return false;
+ }
+
+ return true;
+}
+
int
i915_gem_init_hw(struct drm_device *dev)
{
@@ -3749,7 +3765,7 @@
goto cleanup_render_ring;
}
- if (HAS_BLT(dev)) {
+ if (intel_enable_blt(dev)) {
ret = intel_init_blt_ring_buffer(dev);
if (ret)
goto cleanup_bsd_ring;