From 3a69ddd6f872180b6f61fda87152b37202118fbc Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Fri, 27 Apr 2012 12:44:41 -0700 Subject: [PATCH] drm/i915: Set the Stencil Cache eviction policy to non-LRA mode. Clearing bit 5 of CACHE_MODE_0 is necessary to prevent GPU hangs in OpenGL programs such as Google MapsGL, Google Earth, and gzdoom when using separate stencil buffers. Without it, the GPU tries to use the LRA eviction policy, which isn't supported. This was supposed to be off by default, but seems to be on for many machines. This cannot be done in gen6_init_clock_gating with most of the other workaround bits; the render ring needs to exist. Otherwise, the register write gets dropped on the floor (one printk will show it changed, but a second printk immediately following shows the value reverts to the old one). Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=47535 Cc: stable@vger.kernel.org Cc: Rob Castle Cc: Eric Appleman Cc: aaron667@gmx.net Cc: Keith Packard Signed-off-by: Kenneth Graunke Reviewed-by: Daniel Vetter Acked-by: Daniel Vetter Signed-off-by: Dave Airlie --- drivers/gpu/drm/i915/i915_reg.h | 1 + drivers/gpu/drm/i915/intel_ringbuffer.c | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index b4bb1ef77ddc..9d24d65f0c3e 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -568,6 +568,7 @@ #define CM0_MASK_SHIFT 16 #define CM0_IZ_OPT_DISABLE (1<<6) #define CM0_ZR_OPT_DISABLE (1<<5) +#define CM0_STC_EVICT_DISABLE_LRA_SNB (1<<5) #define CM0_DEPTH_EVICT_DISABLE (1<<4) #define CM0_COLOR_EVICT_DISABLE (1<<3) #define CM0_DEPTH_WRITE_DISABLE (1<<1) diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index f75806e5bff5..80fce51e2f43 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -401,6 +401,14 @@ static int init_render_ring(struct intel_ring_buffer *ring) if (INTEL_INFO(dev)->gen >= 6) { I915_WRITE(INSTPM, INSTPM_FORCE_ORDERING << 16 | INSTPM_FORCE_ORDERING); + + /* From the Sandybridge PRM, volume 1 part 3, page 24: + * "If this bit is set, STCunit will have LRA as replacement + * policy. [...] This bit must be reset. LRA replacement + * policy is not supported." + */ + I915_WRITE(CACHE_MODE_0, + CM0_STC_EVICT_DISABLE_LRA_SNB << CM0_MASK_SHIFT); } return ret; -- 2.20.1