From 3123698f50fe4ac9ddb775dcd2b34a1d9cdd603f Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 13 Sep 2017 11:51:53 +0100 Subject: [PATCH] drm/i915: Use mul_u32_u32() for 32b x 32b -> 64b result MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit As realised by commit 9e3d6223d209 ("math64, timers: Fix 32bit mul_u64_u32_shr() and friends"), GCC does not always generate ideal code for performing a 32b x 32b multiply returning a 64b result (i.e. where we idiomatically use u64 result = (u64)x * (u32)x). This catches a couple of instances in the display code using (u64)x * (u32)y. Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20170913105154.2910-1-chris@chris-wilson.co.uk Reviewed-by: Ville Syrjälä --- drivers/gpu/drm/i915/intel_display.c | 2 +- drivers/gpu/drm/i915/intel_tv.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index c4d8bb7..3bfcf18 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -10224,7 +10224,7 @@ int intel_dotclock_calculate(int link_freq, if (!m_n->link_n) return 0; - return div_u64((u64)m_n->link_m * link_freq, m_n->link_n); + return div_u64(mul_u32_u32(m_n->link_m, link_freq), m_n->link_n); } static void ironlake_pch_clock_get(struct intel_crtc *crtc, diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c index 0cc999f..a79a759 100644 --- a/drivers/gpu/drm/i915/intel_tv.c +++ b/drivers/gpu/drm/i915/intel_tv.c @@ -1385,7 +1385,7 @@ intel_tv_get_modes(struct drm_connector *connector) mode_ptr->vsync_end = mode_ptr->vsync_start + 1; mode_ptr->vtotal = vactive_s + 33; - tmp = (u64) tv_mode->refresh * mode_ptr->vtotal; + tmp = mul_u32_u32(tv_mode->refresh, mode_ptr->vtotal); tmp *= mode_ptr->htotal; tmp = div_u64(tmp, 1000000); mode_ptr->clock = (int) tmp; -- 2.7.4