OMAPDSS: DISPC: fix div by zero issue in overlay scaling

omapdrm doesn't always configure the overlays correctly, causing the
overlay setup functions to be called with zero timings. This leads to
division by zero error.

This happens, for example, when a HDMI cable is not connected, but a
user tries to setup a plane with scaling.

Fixing omapdrm is a big job, so for now let's check for the bad timings
in DISPC and return an error.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Darren Etheridge <detheridge@ti.com>

diff --git a/drivers/video/fbdev/omap2/dss/dispc.c b/drivers/video/fbdev/omap2/dss/dispc.c
index 5aea698b8ad76c941187c982edc28a18f1135ba6..5f2bc849770bac4e459e93584a909b580b160e24 100644 (file)
--- a/drivers/video/fbdev/omap2/dss/dispc.c
+++ b/drivers/video/fbdev/omap2/dss/dispc.c
@@ -2390,6 +2390,11 @@ static int dispc_ovl_calc_scaling(unsigned long pclk, unsigned long lclk,
        if (width == out_width && height == out_height)
                return 0;
 
+       if (pclk == 0 || mgr_timings->pixelclock == 0) {
+               DSSERR("cannot calculate scaling settings: pclk is zero\n");
+               return -EINVAL;
+       }
+
        if ((caps & OMAP_DSS_OVL_CAP_SCALE) == 0)
                return -EINVAL;