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authorTomi Valkeinen <tomi.valkeinen@ti.com>2015-03-17 16:31:10 +0300
committerTomi Valkeinen <tomi.valkeinen@ti.com>2015-06-17 15:38:44 +0300
commitab6b2582b8f931f8f324fbf7bcb8338b8fc1eded (patch)
treeac55ad8baccf611a3aee8d5f99fc9b5a2bb17ea8 /drivers/video
parentf5a734827b07dc907ae95698f91d4b1eaafe9a8a (diff)
downloadlinux-ab6b2582b8f931f8f324fbf7bcb8338b8fc1eded.tar.xz
OMAPDSS: DISPC: add check for scaling limits
On OMAP3/AM43xx some scaling factors cause underflows/synclosts. After studying this, I found that sometimes the driver uses three-tap scaling with downscaling factor smaller than x0.5. This causes issues, as x0.5 is the limit for three-tap scaling. The driver has FEAT_PARAM_DOWNSCALE parameter, but that seems to be for five-tap scaling, which allows scaling down to x0.25. This patch adds checks for both horizontal and vertical scaling. For horizontal the HW always uses 5 taps, so the limit is x0.25. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/fbdev/omap2/dss/dispc.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/video/fbdev/omap2/dss/dispc.c b/drivers/video/fbdev/omap2/dss/dispc.c
index cc61513afdb4..ddce8fcfc5c1 100644
--- a/drivers/video/fbdev/omap2/dss/dispc.c
+++ b/drivers/video/fbdev/omap2/dss/dispc.c
@@ -2326,6 +2326,21 @@ again:
error = (error || in_width > maxsinglelinewidth * 2 ||
(in_width > maxsinglelinewidth && *five_taps) ||
!*core_clk || *core_clk > dispc_core_clk_rate());
+
+ if (!error) {
+ /* verify that we're inside the limits of scaler */
+ if (in_width / 4 > out_width)
+ error = 1;
+
+ if (*five_taps) {
+ if (in_height / 4 > out_height)
+ error = 1;
+ } else {
+ if (in_height / 2 > out_height)
+ error = 1;
+ }
+ }
+
if (error) {
if (*decim_x == *decim_y) {
*decim_x = min_factor;