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| author |   Daniel Vetter <daniel.vetter@ffwll.ch> | 2015-08-12 11:43:34 +0200 |
|---|---|---|
| committer |   Jani Nikula <jani.nikula@intel.com> | 2015-08-13 11:31:56 +0300 |
| commit | e8fa4270536de2e5e8205fb2b90bb26afc471729 (patch) | |
| tree | 5bcf76df151189168a0ae1fd893cdb657b7c2e3a /drivers/gpu/drm | |
| parent | Linux 4.2-rc6 (diff) | |
| download | linux-dev-e8fa4270536de2e5e8205fb2b90bb26afc471729.tar.xz linux-dev-e8fa4270536de2e5e8205fb2b90bb26afc471729.zip | |
drm/i915: Only dither on 6bpc panels
In
commit d328c9d78d64ca11e744fe227096990430a88477
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Fri Apr 10 16:22:37 2015 +0200
drm/i915: Select starting pipe bpp irrespective or the primary plane
we started to select the pipe bpp from sink capabilities and not from
the primary framebuffer - that one might change (and we don't want to
incur a modeset) and sprites might contain higher bpp content too.
We also selected dithering on a 8 bpc screen displaying a 24bpp rgb
primary, because pipe_bpp is 24 for such a typical 8 bpc sink, but since
the commit mentioned above, base_bpp is always the absolute maximum
supported by the hardware, e.g., 36 bpp on my Ironlake chip. Iow. the
only way to not get dithering would have been to connect a deep color 12
bpc display, so pipe_bpp == 36 == base_bpp.
Hence only enable dithering on 6bpc screens where we difinitely and
always want it.
Cc: Mario Kleiner <mario.kleiner.de@gmail.com>
Reported-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-and-tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 30e0f54ba19d..7a03fdc079b7 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -11826,7 +11826,9 @@ encoder_retry: goto encoder_retry; } - pipe_config->dither = pipe_config->pipe_bpp != base_bpp; + /* Dithering seems to not pass-through bits correctly when it should, so + * only enable it on 6bpc panels. */ + pipe_config->dither = pipe_config->pipe_bpp == 6*3; DRM_DEBUG_KMS("plane bpp: %i, pipe bpp: %i, dithering: %i\n", base_bpp, pipe_config->pipe_bpp, pipe_config->dither); |