[Intel-gfx] [PATCH] drm/i915: Skip i915_swizzle_info in platforms without GPU side swizzle

[Michel Thierry]

There's no need to keep reading random registers in i915_swizzle_info if
the platform is not doing GPU side swizzling.

After HSW, swizzling is not used, and the CPU's memory controller
performs all the address swizzling modifications, commit be292e1563ac5b
("drm/i915/bdw: Let the memory controller do all the swizzling").

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Signed-off-by: Michel Thierry <michel.thierry at intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 87e13131f6ea..e82f503389fb 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2152,6 +2152,11 @@ static int i915_swizzle_info(struct seq_file *m, void *data)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
 
+	if (INTEL_GEN(dev_priv) >= 8 || IS_VALLEYVIEW(dev_priv)) {
+		seq_puts(m, "not supported - CPU does all the swizzling\n");
+		return 0;
+	}
+
 	intel_runtime_pm_get(dev_priv);
 
 	seq_printf(m, "bit6 swizzle for X-tiling = %s\n",
-- 
2.11.0