From: Hai Lan <hai.lan@intel.com>
Date: Wed, 15 Feb 2012 11:07:02 +0000 (+0800)
Subject: drm/i915: fix a sprite watermark computation to avoid divide by zero if xpos<0
X-Git-Tag: v3.3-rc6~19^2~4^2~3
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4e9bb47bd29e02f2daaa7bdb2a8ddf977bf76f06;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git

drm/i915: fix a sprite watermark computation to avoid divide by zero if xpos<0

When setting overlay position with x<0, it will divide 0 and make drm
driver crash.

Signed-off-by: Hai Lan <hai.lan@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f3afec2..e654f32 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4680,8 +4680,17 @@ sandybridge_compute_sprite_srwm(struct drm_device *dev, int plane,
 
 	crtc = intel_get_crtc_for_plane(dev, plane);
 	clock = crtc->mode.clock;
+	if (!clock) {
+		*sprite_wm = 0;
+		return false;
+	}
 
 	line_time_us = (sprite_width * 1000) / clock;
+	if (!line_time_us) {
+		*sprite_wm = 0;
+		return false;
+	}
+
 	line_count = (latency_ns / line_time_us + 1000) / 1000;
 	line_size = sprite_width * pixel_size;