Revert "drm/i915: Declare the swizzling unknown for L-shaped configurations"

This reverts commit f711464d345d3801bbbf73b811c96289ff00e128.

It breaks existing old userspace which doesn't handle UNKNOWN
swizzling correct. Yes UNKNOWN was a thing back in 2009 and probably
still is on some other platforms, but it still pretty clearly broke
the testers machine. If we want this we need to extend the ioctl with
new paramters that only new userspace looks at.

Cc: Harald Arnesen <harald@skogtun.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reported-by: Harald Arnesen <harald@skogtun.org>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index d61e74a08f829b1491b61e4557c689546dce9c3f..633bd1fcab6925881048e7310f9aa40e4f9db868 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -183,18 +183,8 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
                if (IS_GEN4(dev)) {
                        uint32_t ddc2 = I915_READ(DCC2);
 
-                       if (!(ddc2 & DCC2_MODIFIED_ENHANCED_DISABLE)) {
-                               /* Since the swizzling may vary within an
-                                * object, we have no idea what the swizzling
-                                * is for any page in particular. Thus we
-                                * cannot migrate tiled pages using the GPU,
-                                * nor can we tell userspace what the exact
-                                * swizzling is for any object.
-                                */
+                       if (!(ddc2 & DCC2_MODIFIED_ENHANCED_DISABLE))
                                dev_priv->quirks |= QUIRK_PIN_SWIZZLED_PAGES;
-                               swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
-                               swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
-                       }
                }
 
                if (dcc == 0xffffffff) {