From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Wed, 24 Jan 2018 20:36:42 +0200
Subject: drm/i915: Assert that we don't overflow frontbuffer tracking bits
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Git-commit: aa81e2c334824d399f16e7cabe272ebf3c0e43df
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
Add some compile time assrts to the frontbuffer tracking to make sure
that we have enough bits per pipe to cover all the planes, and that we
have enough total bits to cover all the planes across all pipes.
We'll ignore any potential clash between the overlay bit and the
plane bits because that will allow us to keep using a total of 32
bits for the foreseeable future.
While at it change the macros to use BIT() and GENMASK(). The latter
gets rid of the hardcoded 0xff and thus means we can change the
number of bits per pipe by just changing
INTEL_FRONTBUFFER_BITS_PER_PIPE.
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180124183642.32549-1-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/i915/i915_drv.h | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2429,12 +2429,16 @@ enum hdmi_force_audio {
* We have one bit per pipe and per scanout plane type.
*/
#define INTEL_FRONTBUFFER_BITS_PER_PIPE 8
-#define INTEL_FRONTBUFFER(pipe, plane_id) \
- (1 << ((plane_id) + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
+#define INTEL_FRONTBUFFER(pipe, plane_id) ({ \
+ BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 32); \
+ BUILD_BUG_ON(I915_MAX_PLANES > INTEL_FRONTBUFFER_BITS_PER_PIPE); \
+ BIT((plane_id) + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)); \
+})
#define INTEL_FRONTBUFFER_OVERLAY(pipe) \
- (1 << (INTEL_FRONTBUFFER_BITS_PER_PIPE - 1 + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
+ BIT(INTEL_FRONTBUFFER_BITS_PER_PIPE - 1 + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))
#define INTEL_FRONTBUFFER_ALL_MASK(pipe) \
- (0xff << (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
+ GENMASK(INTEL_FRONTBUFFER_BITS_PER_PIPE * ((pipe) + 1) - 1, \
+ INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))
/*
* Optimised SGL iterator for GEM objects