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| author | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2015-03-17 15:31:10 +0200 |
|---|---|---|
| committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2015-06-17 15:38:44 +0300 |
| commit | ab6b2582b8f931f8f324fbf7bcb8338b8fc1eded (patch) | |
| tree | ac55ad8baccf611a3aee8d5f99fc9b5a2bb17ea8 /drivers/video | |
| parent | f5a734827b07dc907ae95698f91d4b1eaafe9a8a (diff) | |
| download | linux-ab6b2582b8f931f8f324fbf7bcb8338b8fc1eded.tar.bz2 | |
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.c | 15 |
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; |