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drm/vc4: ->x_scaling[1] should never be set to VC4_SCALING_NONE

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For the YUV conversion to work properly, ->x_scaling[1] should never
be set to VC4_SCALING_NONE, but vc4_get_scaling_mode() might return
VC4_SCALING_NONE if the horizontal scaling ratio exactly matches the
horizontal subsampling factor. Add a test to turn VC4_SCALING_NONE
into VC4_SCALING_PPF when that happens.

The old ->x_scaling[0] adjustment is dropped as I couldn't find any
mention to this constraint in the spec and it's proven to be
unnecessary (I tested various multi-planar YUV formats with scaling
disabled, and all of them worked fine without this adjustment).

Fixes: fc04023faf ("drm/vc4: Add support for YUV planes.")
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20181109102633.32603-1-boris.brezillon@bootlin.com
This commit is contained in:
Boris Brezillon 2018-11-09 11:26:32 +01:00
parent 65bf2d54f0
commit 0560054da5
1 changed files with 7 additions and 5 deletions
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12
drivers/gpu/drm/vc4/vc4_plane.c
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@ -341,12 +341,14 @@ static int vc4_plane_setup_clipping_and_scaling(struct drm_plane_state *state)
vc4_get_scaling_mode(vc4_state->src_h[1],
vc4_state->crtc_h);
/* YUV conversion requires that horizontal scaling be enabled,
* even on a plane that's otherwise 1:1. Looks like only PPF
* works in that case, so let's pick that one.
/* YUV conversion requires that horizontal scaling be enabled
* on the UV plane even if vc4_get_scaling_mode() returned
* VC4_SCALING_NONE (which can happen when the down-scaling
* ratio is 0.5). Let's force it to VC4_SCALING_PPF in this
* case.
*/
if (vc4_state->is_unity)
vc4_state->x_scaling[0] = VC4_SCALING_PPF;
if (vc4_state->x_scaling[1] == VC4_SCALING_NONE)
vc4_state->x_scaling[1] = VC4_SCALING_PPF;
} else {
vc4_state->is_yuv = false;
vc4_state->x_scaling[1] = VC4_SCALING_NONE;