[Intel-gfx] [PATCH] drm/i915: Report the actual swizzling back to userspace

[Chris Wilson]

Userspace cares about whether or not swizzling depends on the page
address for its direct access into bound objects. Extend the get_tiling
ioctl to report the physical swizzling value in addition to the logical
swizzling value so that userspace can accurately determine when it is
possible for manual detiling.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Akash Goel <akash.goel at intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem_tiling.c | 1 +
 include/uapi/drm/i915_drm.h            | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index 3c073fb58730..b53ec941f17e 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -446,6 +446,7 @@ i915_gem_get_tiling(struct drm_device *dev, void *data,
 	}
 
 	/* Hide bit 17 from the user -- see comment in i915_gem_set_tiling */
+	args->phys_swizzle_mode = args->swizzle_mode;
 	if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
 		args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
 	if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 7615ae68e015..5ff86692e03e 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -934,6 +934,12 @@ struct drm_i915_gem_get_tiling {
 	 * mmap mapping.
 	 */
 	__u32 swizzle_mode;
+
+	/**
+	 * Returned address bit 6 swizzling required for CPU access through
+	 * mmap mapping whilst bound.
+	 */
+	__u32 phys_swizzle_mode;
 };
 
 struct drm_i915_gem_get_aperture {
-- 
2.1.1