[Intel-gfx] [PATCH] drm/i915/bdw: Only use 2g GGTT for 32b platforms
Ben Widawsky
benjamin.widawsky at intel.com
Wed May 7 06:58:59 CEST 2014
From: Ben Widawsky <benjamin.widawsky at linux.intel.com>
Daniel requested in the bug that I use a 3GB fallback size. Since this
is not in the spec as a valid size, I decided against it. We could
potentially add a patch to bump it to 3GB on top of this one.
This probably should be CC: stable - but I'll let the powers that be
decide that one.
v2: Change ifdef to 32b, instead of ifndef
update comment
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76619
Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 846b6ee..d03a540 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1759,6 +1759,14 @@ static inline unsigned int gen8_get_total_gtt_size(u16 bdw_gmch_ctl)
bdw_gmch_ctl &= BDW_GMCH_GGMS_MASK;
if (bdw_gmch_ctl)
bdw_gmch_ctl = 1 << bdw_gmch_ctl;
+
+#ifdef CONFIG_32BIT
+ /* Limit 32B platforms to a 2GB GGTT
+ 4 << 20 / pte size * PAGE_SIZE */
+ if (bdw_gmch_ctl > 4)
+ bdw_gmch_ctl = 4;
+#endif
+
return bdw_gmch_ctl << 20;
}
--
1.9.2
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