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| author | Chandrabhanu Mahapatra <cmahapatra@ti.com> | 2011-12-19 12:33:44 +0400 |
|---|---|---|
| committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-01-02 10:51:29 +0400 |
| commit | debd90749b7440ad5fc02e4f0d1e8a696385f196 (patch) | |
| tree | fdde45a42f4bba25a323c246d213d8bebfdfa9cf /drivers/video/omap2/dss/dispc.h | |
| parent | 1f3f53ae5179ba7f24b4a429bc41773f1f4857ca (diff) | |
| download | linux-debd90749b7440ad5fc02e4f0d1e8a696385f196.tar.xz | |
OMAPDSS: DISPC: Update Fir Coefficients
The FIR coefficients present in kernel are being updated to new coefficients
consisting of 24 coefficient tables, with 12 each for 3 tap and 5 tap scenario,
which are chosen on the basis of DISPC up/downsampling filters M value. M is
the inverse of low pass cut off frequency of the sampling filter. For vertical
scaling 3 tap or 5 tap tables are used based on the clock rate and width of
the line buffer whereas in OMAP2 3 tap is always used. For horizontal scaling
however 5 tap tables are always used.
New coefficients and the corresponding logic have been tested on OMAP2, OMAP3
and OMAP4. Horizontal and vertical scaling worked fine except for some 3 tap
vs 5 tap issue during vertical upscaling and clock failing issues which is
acknowledged in the next patch. Vertical upscaling was found to perform better
under 5 taps. The 24 coefficient tables have been moved to another file
dispc_coefs.c for proper maintainance.
This code is written based on code written by Lajos Molnar <lajos@ti.com> in
Android Kernel for scaling. Lajos Molnar <lajos@ti.com> had fine tuned the FIR
coefficient selection process and reduced outliness and blockiness around
images when upscaling more than 2 times.
Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Diffstat (limited to 'drivers/video/omap2/dss/dispc.h')
| -rw-r--r-- | drivers/video/omap2/dss/dispc.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/video/omap2/dss/dispc.h b/drivers/video/omap2/dss/dispc.h index c06efc38983e..5836bd1650f9 100644 --- a/drivers/video/omap2/dss/dispc.h +++ b/drivers/video/omap2/dss/dispc.h @@ -97,6 +97,17 @@ #define DISPC_OVL_PRELOAD(n) (DISPC_OVL_BASE(n) + \ DISPC_PRELOAD_OFFSET(n)) +/* DISPC up/downsampling FIR filter coefficient structure */ +struct dispc_coef { + s8 hc4_vc22; + s8 hc3_vc2; + u8 hc2_vc1; + s8 hc1_vc0; + s8 hc0_vc00; +}; + +const struct dispc_coef *dispc_ovl_get_scale_coef(int inc, int five_taps); + /* DISPC manager/channel specific registers */ static inline u16 DISPC_DEFAULT_COLOR(enum omap_channel channel) { |