drm/i915: limit PPGTT size to 2GB in 32-bit platforms

We already set this limit for the GGTT.

This is a temporary patch until a full replacement of size_t variables
(inadequate in 32-bit kernel) is in place.

Regression from:
	commit a4e0bedca678c81eea4cd79a4bd502335639f73a
	Author: Michel Thierry <michel.thierry@intel.com>
	Date:   Wed Apr 8 12:13:35 2015 +0100

		drm/i915: Use complete address space in true PPGTT

v2: Prettify code and explain why this is needed. (Chris)
v3: Don't hide the compilation warning in 32-bit. (Chris)

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 17b7df0b561f1bdc2476060b8eabbd34095c377a..619dad1b23863716972a23b12226b16af533a068 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -952,6 +952,13 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
 
        ppgtt->base.start = 0;
        ppgtt->base.total = 1ULL << 32;
+       if (IS_ENABLED(CONFIG_X86_32))
+               /* While we have a proliferation of size_t variables
+                * we cannot represent the full ppgtt size on 32bit,
+                * so limit it to the same size as the GGTT (currently
+                * 2GiB).
+                */
+               ppgtt->base.total = to_i915(ppgtt->base.dev)->gtt.base.total;
        ppgtt->base.cleanup = gen8_ppgtt_cleanup;
        ppgtt->base.allocate_va_range = gen8_alloc_va_range;
        ppgtt->base.insert_entries = gen8_ppgtt_insert_entries;