[PATCH 06/10] drm/tegra: Handle 64-bit return from drm_crtc_vblank_count()

Dhinakaran Pandiyan
2018-02-03T05:12:58Z

570e86963a51 ("drm: Widen vblank count to 64-bits [v3]") changed the
return type for drm_crtc_vblank_count() to u64. This could cause
potential problems if the return value is used in arithmetic operations
with a 32-bit reference HW vblank count. Explicitly typecasting this
down to u32 either fixes a potential problem or serves to add clarity in
case the implicit typecasting was already correct.

Cc: Keith Packard <keithp@keithp.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
---
drivers/gpu/drm/tegra/dc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index b8403ed48285..49df2db2ad46 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -1359,7 +1359,7 @@ static u32 tegra_dc_get_vblank_counter(struct drm_crtc *crtc)
return host1x_syncpt_read(dc->syncpt);

/* fallback to software emulated VBLANK counter */
- return drm_crtc_vblank_count(&dc->base);
+ return (u32)drm_crtc_vblank_count(&dc->base);
}

static int tegra_dc_enable_vblank(struct drm_crtc *crtc)
--
2.14.1