From aa81e2c334824d399f16e7cabe272ebf3c0e43df Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Wed, 24 Jan 2018 20:36:42 +0200 Subject: [PATCH] drm/i915: Assert that we don't overflow frontbuffer tracking bits MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20180124183642.32549-1-ville.syrjala@linux.intel.com Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/i915_drv.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 0d8cb74e7d02..816183da06de 100644 --- 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 -- 2.30.2