[Intel-gfx] [PATCH] [v2] drm/i915: Fix context sizes on HSW

[Ben Widawsky]

With updates to the spec, we can actually see the context layout, and
how many dwords are allocated. That table suggests we need 70720 bytes
per HW context. Rounded up, this is 18 pages. Looking at what lives
after the current 4 pages we use, I can't see too much important (mostly
it's d3d related), but there are a couple of things which look scary. I
am hopeful this can explain some of our odd HSW failures.

v2: Make the context only 17 pages. The power context space isn't used
ever, and execlists aren't used in our driver, making the actual total
66944 bytes.

Reported-by: "Azad, Vinit" <vinit.azad at intel.com>
Cc: stable at vger.kernel.org
Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 2 +-
 drivers/gpu/drm/i915/i915_reg.h         | 9 +--------
 2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index ff47145..51b7a21 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -113,7 +113,7 @@ static int get_context_size(struct drm_device *dev)
 	case 7:
 		reg = I915_READ(GEN7_CXT_SIZE);
 		if (IS_HASWELL(dev))
-			ret = HSW_CXT_TOTAL_SIZE(reg) * 64;
+			ret = HSW_CXT_TOTAL_SIZE;
 		else
 			ret = GEN7_CXT_TOTAL_SIZE(reg) * 64;
 		break;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2102ff3..f061c67 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1718,14 +1718,7 @@
 					 GEN7_CXT_EXTENDED_SIZE(ctx_reg) + \
 					 GEN7_CXT_GT1_SIZE(ctx_reg) + \
 					 GEN7_CXT_VFSTATE_SIZE(ctx_reg))
-#define HSW_CXT_POWER_SIZE(ctx_reg)	((ctx_reg >> 26) & 0x3f)
-#define HSW_CXT_RING_SIZE(ctx_reg)	((ctx_reg >> 23) & 0x7)
-#define HSW_CXT_RENDER_SIZE(ctx_reg)	((ctx_reg >> 15) & 0xff)
-#define HSW_CXT_TOTAL_SIZE(ctx_reg)	(HSW_CXT_POWER_SIZE(ctx_reg) + \
-					 HSW_CXT_RING_SIZE(ctx_reg) + \
-					 HSW_CXT_RENDER_SIZE(ctx_reg) + \
-					 GEN7_CXT_VFSTATE_SIZE(ctx_reg))
-
+#define HSW_CXT_TOTAL_SIZE		(17 * PAGE_SIZE)
 
 /*
  * Overlay regs
-- 
1.8.3