From eed02a7b53131abb796ba8a8cf2886cee366a89f Mon Sep 17 00:00:00 2001
From: "Kumar, Mahesh" <mahesh1.kumar@intel.com>
Date: Wed, 5 Jul 2017 20:01:45 +0530
Subject: [PATCH] drm/i915: Always perform internal fixed16 division in 64 bits
Git-commit: eed02a7b53131abb796ba8a8cf2886cee366a89f
Patch-mainline: v4.14-rc1
References: FATE#322643 bsc#1055900
This patch combines fixed_16_16_div & fixed_16_16_div_u64 wrappers.
And new fixed_16_16_div wrapper always performs division operation in
u64 internally, to avoid any data loss which was happening in earlier
version of wrapper.
earlier wrapper was converting u32 to fixed16 in 32 bit so we were
losing 16-MSB data.
Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170705143154.32132-3-mahesh1.kumar@intel.com
[mlankhorst: Fix typo in commit message.]
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/i915_drv.h | 9 ---------
drivers/gpu/drm/i915/intel_pm.c | 4 ++--
2 files changed, 2 insertions(+), 11 deletions(-)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -197,15 +197,6 @@ static inline uint_fixed_16_16_t mul_fix
static inline uint_fixed_16_16_t fixed_16_16_div(uint32_t val, uint32_t d)
{
- uint_fixed_16_16_t fp, res;
-
- fp = u32_to_fixed_16_16(val);
- res.val = DIV_ROUND_UP(fp.val, d);
- return res;
-}
-
-static inline uint_fixed_16_16_t fixed_16_16_div_u64(uint32_t val, uint32_t d)
-{
uint64_t interm_val;
interm_val = (uint64_t)val << 16;
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4276,7 +4276,7 @@ static uint_fixed_16_16_t skl_wm_method1
return FP_16_16_MAX;
wm_intermediate_val = latency * pixel_rate * cpp;
- ret = fixed_16_16_div_u64(wm_intermediate_val, 1000 * 512);
+ ret = fixed_16_16_div(wm_intermediate_val, 1000 * 512);
return ret;
}
@@ -4314,7 +4314,7 @@ intel_get_linetime_us(struct intel_crtc_
return u32_to_fixed_16_16(0);
crtc_htotal = cstate->base.adjusted_mode.crtc_htotal;
- linetime_us = fixed_16_16_div_u64(crtc_htotal * 1000, pixel_rate);
+ linetime_us = fixed_16_16_div(crtc_htotal * 1000, pixel_rate);
return linetime_us;
}