Hi Philipp,

Thanks for this great patchset! Finally we have improved seams
with tiled conversions, and relaxed width alignment requirements.

Unfortunately this patchset isn't working correctly yet. It breaks tiled
conversions with rotation.

Trying the following conversion:

input: 720x480, UYVY
output: 1280x768, UYVY, rotation=90 degrees

causes non-8-byte aligned tile buffers at the output:

[  129.578210] imx-ipuv3 2400000.ipu: task 2: ctx 8955dec9: Input@[0,0]: phys 00000000 [  129.585980] imx-ipuv3 2400000.ipu: task 2: ctx 8955dec9: Input@[1,0]: phys 00051360 [  129.593736] imx-ipuv3 2400000.ipu: task 2: ctx 8955dec9: Output@[0,0]: phys 00000000 [  129.601556] imx-ipuv3 2400000.ipu: task 2: ctx 8955dec9: Output@[0,1]: phys 0000052e

resulting in hung conversion and abort timeout:

[  147.689220] imx-ipuv3 2400000.ipu: ipu_image_convert_abort: timeout

Note that when converting to a planar format, the final (rotated) chroma tile
buffers are also mis-aligned, in addition to the Y buffers.

I have some additional comments to follow in the patches.

Steve

On 06/22/2018 08:52 AM, Philipp Zabel wrote:
Hi,

we have image conversion code for scaling and colorspace conversion in
the IPUv3 base driver for a while. Since the IC hardware can only write
up to 1024x1024 pixel buffers, it scales to larger output buffers by
splitting the input and output frame into similarly sized tiles.

This causes the issue that the bilinear interpolation resets at the tile
boundary: instead of smoothly interpolating across the seam, there is a
jump in the input sample position that is very apparent for high
upscaling factors. This can be avoided by slightly changing the scaling
coefficients to let the left/top tiles overshoot their input sampling
into the first pixel / line of their right / bottom neighbors. The error
can be further reduced by letting tiles be differently sized and by
selecting seam positions that minimize the input sampling position error
at tile boundaries.
This is complicated by different DMA start address, burst size, and
rotator block size alignment requirements, depending on the input and
output pixel formats, and the fact that flipping happens in different
places depending on the rotation.

This series implements optimal seam position selection and seam hiding
with per-tile resizing coefficients and adds a scaling mem2mem device
to the imx-media driver.

regards
Philipp

Philipp Zabel (16):
   gpu: ipu-v3: ipu-ic: allow to manually set resize coefficients
   gpu: ipu-v3: image-convert: prepare for per-tile configuration
   gpu: ipu-v3: image-convert: calculate per-tile resize coefficients
   gpu: ipu-v3: image-convert: reconfigure IC per tile
   gpu: ipu-v3: image-convert: store tile top/left position
   gpu: ipu-v3: image-convert: calculate tile dimensions and offsets
     outside fill_image
   gpu: ipu-v3: image-convert: move tile alignment helpers
   gpu: ipu-v3: image-convert: select optimal seam positions
   gpu: ipu-v3: image-convert: fix debug output for varying tile sizes
   gpu: ipu-v3: image-convert: relax tile width alignment for NV12 and
     NV16
   gpu: ipu-v3: image-convert: relax input alignment restrictions
   gpu: ipu-v3: image-convert: relax output alignment restrictions
   gpu: ipu-v3: image-convert: fix bytesperline adjustment
   gpu: ipu-v3: image-convert: add some ASCII art to the exposition
   gpu: ipu-v3: image-convert: disable double buffering if necessary
   media: imx: add mem2mem device

  drivers/gpu/ipu-v3/ipu-ic.c                   |  52 +-
  drivers/gpu/ipu-v3/ipu-image-convert.c        | 865 +++++++++++++---
  drivers/staging/media/imx/Kconfig             |   1 +
  drivers/staging/media/imx/Makefile            |   1 +
  drivers/staging/media/imx/imx-media-dev.c     |  11 +
  drivers/staging/media/imx/imx-media-mem2mem.c | 953 ++++++++++++++++++
  drivers/staging/media/imx/imx-media.h         |  10 +
  include/video/imx-ipu-v3.h                    |   6 +
  8 files changed, 1760 insertions(+), 139 deletions(-)
  create mode 100644 drivers/staging/media/imx/imx-media-mem2mem.c


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