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[06/11] OMAPDSS: DISPC: fix 64 bit issue in 5-tap

Message ID 1434545675-477-7-git-send-email-tomi.valkeinen@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Tomi Valkeinen June 17, 2015, 12:54 p.m. UTC 
The DISPC driver uses 64 bit arithmetic to calculate the required clock
rate for scaling. The code does not seem to work correctly, and instead
calculates with 32 bit numbers, giving wrong result.

Fix the code by typecasting values to u64 first, so that the
calculations do happen in 64 bits.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
---
 drivers/video/fbdev/omap2/dss/dispc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/video/fbdev/omap2/dss/dispc.c b/drivers/video/fbdev/omap2/dss/dispc.c
index 4488d9367bd3..2db1c986e989 100644
--- a/drivers/video/fbdev/omap2/dss/dispc.c
+++ b/drivers/video/fbdev/omap2/dss/dispc.c
@@ -2166,7 +2166,7 @@  static unsigned long calc_core_clk_five_taps(unsigned long pclk,
 	if (height > out_height) {
 		unsigned int ppl = mgr_timings->x_res;
 
-		tmp = pclk * height * out_width;
+		tmp = (u64)pclk * height * out_width;
 		do_div(tmp, 2 * out_height * ppl);
 		core_clk = tmp;
 
@@ -2174,14 +2174,14 @@  static unsigned long calc_core_clk_five_taps(unsigned long pclk,
 			if (ppl == out_width)
 				return 0;
 
-			tmp = pclk * (height - 2 * out_height) * out_width;
+			tmp = (u64)pclk * (height - 2 * out_height) * out_width;
 			do_div(tmp, 2 * out_height * (ppl - out_width));
 			core_clk = max_t(u32, core_clk, tmp);
 		}
 	}
 
 	if (width > out_width) {
-		tmp = pclk * width;
+		tmp = (u64)pclk * width;
 		do_div(tmp, out_width);
 		core_clk = max_t(u32, core_clk, tmp);