[PATCH] OMAPDSS: DISPC: Fix 34xx overlay scaling calculation

From: Ivaylo Dimitrov
Date: Sat Jan 11 2014 - 07:43:24 EST


From: Ivaylo Dimitrov <freemangordon@xxxxxx>

commit 7faa92339bbb1e6b9a80983b206642517327eb75 OMAPDSS: DISPC: Handle
synclost errors in OMAP3 introduces limits check to prevent SYNCLOST errors
on OMAP3. However, it misses the logic found in Nokia kernels that is
needed to correctly calculate whether 3 tap or 5 tap rescaler to be used as
well as the logic to fallback to 3 taps if 5 taps clock results in too
tight horizontal timings. Without that patch "horizontal timing too tight"
errors are seen when a video with resolution above 640x350 is tried to be
played. The patch is a forward-ported logic found in Nokia N900 and N9/50
kernels.

Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@xxxxxxxxx>
---
drivers/video/omap2/dss/dispc.c | 36 +++++++++++++++++++++++++-----------
1 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 67e413e..9d1aa25 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1999,7 +1999,8 @@ static void calc_tiler_rotation_offset(u16 screen_width, u16 width,
*/
static int check_horiz_timing_omap3(unsigned long pclk, unsigned long lclk,
const struct omap_video_timings *t, u16 pos_x,
- u16 width, u16 height, u16 out_width, u16 out_height)
+ u16 width, u16 height, u16 out_width, u16 out_height,
+ bool five_taps)
{
const int ds = DIV_ROUND_UP(height, out_height);
unsigned long nonactive;
@@ -2019,6 +2020,10 @@ static int check_horiz_timing_omap3(unsigned long pclk, unsigned long lclk,
if (blank <= limits[i])
return -EINVAL;

+ /* FIXME add checks for 3-tap filter once the limitations are known */
+ if (!five_taps)
+ return 0;
+
/*
* Pixel data should be prepared before visible display point starts.
* So, atleast DS-2 lines must have already been fetched by DISPC
@@ -2191,24 +2196,33 @@ static int dispc_ovl_calc_scaling_34xx(unsigned long pclk, unsigned long lclk,
const int maxsinglelinewidth =
dss_feat_get_param_max(FEAT_PARAM_LINEWIDTH);

+ *five_taps = height > out_height;
+
do {
in_height = DIV_ROUND_UP(height, *decim_y);
in_width = DIV_ROUND_UP(width, *decim_x);
- *core_clk = calc_core_clk_five_taps(pclk, mgr_timings,
- in_width, in_height, out_width, out_height, color_mode);
-
- error = check_horiz_timing_omap3(pclk, lclk, mgr_timings,
- pos_x, in_width, in_height, out_width,
- out_height);

if (in_width > maxsinglelinewidth)
if (in_height > out_height &&
in_height < out_height * 2)
*five_taps = false;
- if (!*five_taps)
+again:
+ if (*five_taps)
+ *core_clk = calc_core_clk_five_taps(pclk, mgr_timings,
+ in_width, in_height, out_width,
+ out_height, color_mode);
+ else
*core_clk = dispc.feat->calc_core_clk(pclk, in_width,
- in_height, out_width, out_height,
- mem_to_mem);
+ in_height, out_width, out_height,
+ mem_to_mem);
+
+ error = check_horiz_timing_omap3(pclk, lclk, mgr_timings,
+ pos_x, in_width, in_height, out_width,
+ out_height, *five_taps);
+ if (error && *five_taps) {
+ *five_taps = false;
+ goto again;
+ }

error = (error || in_width > maxsinglelinewidth * 2 ||
(in_width > maxsinglelinewidth && *five_taps) ||
@@ -2226,7 +2240,7 @@ static int dispc_ovl_calc_scaling_34xx(unsigned long pclk, unsigned long lclk,
} while (*decim_x <= *x_predecim && *decim_y <= *y_predecim && error);

if (check_horiz_timing_omap3(pclk, lclk, mgr_timings, pos_x, width,
- height, out_width, out_height)){
+ height, out_width, out_height, *five_taps)) {
DSSERR("horizontal timing too tight\n");
return -EINVAL;
}
--
1.5.6.1

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