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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-09-13 13:51:53 +0300 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2017-09-13 15:27:20 +0300 |
| commit | 3123698f50fe4ac9ddb775dcd2b34a1d9cdd603f (patch) | |
| tree | 19bf0a89fe2f609d5bb4a8cdbfb00c20ed280502 | |
| parent | e60b36f76c2ee0ba90b431daa534bc262798fb26 (diff) | |
| download | linux-3123698f50fe4ac9ddb775dcd2b34a1d9cdd603f.tar.xz | |
drm/i915: Use mul_u32_u32() for 32b x 32b -> 64b result
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 <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20170913105154.2910-1-chris@chris-wilson.co.uk
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 2 | ||||
| -rw-r--r-- | 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 c4d8bb75686a..3bfcf187a0a1 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 0cc999fa09c5..a79a7591b2cf 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; |