drm/i915: try not to lose backlight CBLV precision

[firefly-linux-kernel-4.4.55.git] / drivers / gpu / drm / i915 / intel_opregion.c

diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
index cfb8fb68f09c87e7da468a57dd2375530ddc0345..119771ff46ab5178047c018efc5f9f31a06f068d 100644 (file)
--- a/drivers/gpu/drm/i915/intel_opregion.c
+++ b/drivers/gpu/drm/i915/intel_opregion.c
@@ -173,7 +173,7 @@ static u32 asle_set_backlight(struct drm_device *dev, u32 bclp)
                return ASLE_BACKLIGHT_FAILED;
 
        intel_panel_set_backlight(dev, bclp, 255);
-       iowrite32((bclp*0x64)/0xff | ASLE_CBLV_VALID, &asle->cblv);
+       iowrite32(DIV_ROUND_UP(bclp * 100, 255) | ASLE_CBLV_VALID, &asle->cblv);
 
        return 0;
 }