[RFC][PATCH 0/5] Introduce drm scaling filter property

[Laxminarayan Bharadiya, Pankaj]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: 12 March 2020 19:35
> To: Laxminarayan Bharadiya, Pankaj
> <pankaj.laxminarayan.bharadiya at intel.com>
> Cc: jani.nikula at linux.intel.com; daniel at ffwll.ch; intel-
> gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org; airlied at linux.ie;
> maarten.lankhorst at linux.intel.com; tzimmermann at suse.de;
> mripard at kernel.org; mihail.atanassov at arm.com; linux-
> kernel at vger.kernel.org; Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>
> Subject: Re: [RFC][PATCH 0/5] Introduce drm scaling filter property
> 
> On Tue, Feb 25, 2020 at 12:35:40PM +0530, Pankaj Bharadiya wrote:
> > Integer scaling (IS) is a nearest-neighbor upscaling technique that
> > simply scales up the existing pixels by an integer (i.e., whole
> > number) multiplier. Nearest-neighbor (NN) interpolation works by
> > filling in the missing color values in the upscaled image with that of
> > the coordinate-mapped nearest source pixel value.
> >
> > Both IS and NN preserve the clarity of the original image. In
> > contrast, traditional upscaling algorithms, such as bilinear or
> > bicubic interpolation, result in blurry upscaled images because they
> > employ interpolation techniques that smooth out the transition from
> > one pixel to another.  Therefore, integer scaling is particularly
> > useful for pixel art games that rely on sharp, blocky images to
> > deliver their distinctive look.
> >
> > Many gaming communities have been asking for integer-mode scaling
> > support, some links and background:
> >
> > https://software.intel.com/en-us/articles/integer-scaling-support-on-i
> > ntel-graphics http://tanalin.com/en/articles/lossless-scaling/
> > https://community.amd.com/thread/209107
> > https://www.nvidia.com/en-us/geforce/forums/game-ready-drivers/13/1002
> > /feature-request-nonblurry-upscaling-at-integer-rat/
> >
> > This patch series -
> >   - Introduces new scaling filter property to allow userspace to
> >     select  the driver's default scaling filter or Nearest-neighbor(NN)
> >     filter for scaling operations on crtc/plane.
> >   - Implements and enable integer scaling for i915
> >
> > Userspace patch series link: TBD.
> 
> That needs to be done or this will go nowhere.

Yes, Sameer is working on enabling this feature in Kodi. 
Sameer, please share link here once you post patches.
 
Thanks,
Pankaj

> 
> >
> > Thanks to Shashank for initiating this work. His initial RFC can be
> > found here [1]
> >
> > [1] https://patchwork.freedesktop.org/patch/337082/
> >
> > Modifications done in this series -
> >    - refactored code and incorporated initial review comments and
> >      added 2 scaling filter types (default and NN) to begin with.
> >    - added scaling filter property support for planes and new API
> >      helpers for drivers to setup this property.
> >    - rewrote code to enable integer scaling and NN filter for i915
> >
> >
> > Pankaj Bharadiya (5):
> >   drm: Introduce scaling filter property
> >   drm/drm-kms.rst: Add Scaling filter property documentation
> >   drm/i915: Enable scaling filter for plane and pipe
> >   drm/i915: Introduce scaling filter related registers and bit fields.
> >   drm/i915/display: Add Nearest-neighbor based integer scaling support
> >
> >  Documentation/gpu/drm-kms.rst                |   6 ++
> >  drivers/gpu/drm/drm_atomic_uapi.c            |   8 ++
> >  drivers/gpu/drm/drm_crtc.c                   |  16 +++
> >  drivers/gpu/drm/drm_mode_config.c            |  13 +++
> >  drivers/gpu/drm/drm_plane.c                  |  35 +++++++
> >  drivers/gpu/drm/i915/display/intel_display.c | 100 ++++++++++++++++++-
> >  drivers/gpu/drm/i915/display/intel_display.h |   2 +
> >  drivers/gpu/drm/i915/display/intel_sprite.c  |  32 ++++--
> >  drivers/gpu/drm/i915/i915_reg.h              |  21 ++++
> >  include/drm/drm_crtc.h                       |  10 ++
> >  include/drm/drm_mode_config.h                |   6 ++
> >  include/drm/drm_plane.h                      |  14 +++
> >  12 files changed, 252 insertions(+), 11 deletions(-)
> >
> > --
> > 2.23.0
> 
> --
> Ville Syrjälä
> Intel