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Subject[PATCH] drm/drm_vblank.c: avoid unsigned int to signed int cast
Date
From: Sui Jingfeng <suijingfeng@loongson.cn>

Both mode->crtc_htotal and mode->crtc_vtotal are u16 type,
mode->crtc_htotal * mode->crtc_vtotal will results a unsigned type.
Using a u32 is enough to store the result, but considering that the
result will be casted to u64 soon after. We use a u64 type directly.
So there no need to cast it to signed type and cast back then.

Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Cc: loongson-kernel@lists.loongnix.cn
---
drivers/gpu/drm/drm_vblank.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 877e2067534f..d99c404b181b 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -622,7 +622,7 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc,

/* Valid dotclock? */
if (dotclock > 0) {
- int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
+ u64 frame_size = mode->crtc_htotal * mode->crtc_vtotal;

/*
* Convert scanline length in pixels and video
@@ -630,7 +630,7 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc,
* in nanoseconds:
*/
linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
- framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
+ framedur_ns = div_u64(frame_size * 1000000, dotclock);

/*
* Fields of interlaced scanout modes are only half a frame duration.
--
2.25.1
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