[Intel-gfx] [PATCH v2 15/23] drm/i915/dsc: Define & Compute VESA DSC params

Manasi Navare manasi.d.navare at intel.com
Wed Sep 5 20:04:48 UTC 2018


Gaurav,

Please find my review comments below. Caught them when I tested
your patch on DSC sink.

On Tue, Jul 31, 2018 at 02:07:11PM -0700, Manasi Navare wrote:
> From: Gaurav K Singh <gaurav.k.singh at intel.com>
> 
> This patches does the following:
> 
> 1. This patch defines all the DSC parameters as per the VESA
> DSC specification. These are stored in the encoder and used
> to compute the PPS parameters to be sent to the Sink.
> 2. Compute all the DSC parameters which are derived from DSC
> state of intel_crtc_state.
> 3. Compute all parameters that are VESA DSC specific
> 
> This computation happens in the atomic check phase during
> compute_config() to validate if display stream compression
> can be enabled for the requested mode.
> 
> v5 (From Manasi):
> * Add logic to limit the max line buf depth for DSC 1.1 to 13
> as per DSC 1.1 spec
> * Fix dim checkpatch warnings/checks
> 
> v4 (From Gaurav):
> * Rebase on latest drm tip
> * rename variable name(Manasi)
> * Populate linebuf_depth variable(Manasi)
> 
> v3 (From Gaurav):
> * Rebase my previous patches on top of Manasi's latest patch
> series
> * Using >>n rather than /2^n (Manasi)
> * Change the commit message to explain what the patch is doing(Gaurav)
> 
> Fixed review comments from Ville:
> * Don't use macro TWOS_COMPLEMENT
> * Mention in comment about the source of RC params
> * Return directly from case statements
> * Using single asssignment for assigning rc_range_params
> * Using <<n rather than *2^n and removing the comments
> about the fixed point numbers
> 
> v2 (From Manasi):
> * Update logic for minor version to consider the dpcd value
> and what supported by the HW platform
> * Use DRM DSC config struct instead of intel_dp struct
> * Move the DSC constants to DRM DSC header file
> * Use u16, u8 where bigger data types not needed
> * * Compute the DSC parameters as part of DSC compute config
> since the computation can fail (Manasi)
> 
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
> Cc: Gaurav K Singh <gaurav.k.singh at intel.com>
> Signed-off-by: Gaurav K Singh <gaurav.k.singh at intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> ---
>  drivers/gpu/drm/i915/Makefile     |   3 +-
>  drivers/gpu/drm/i915/intel_dp.c   |   7 +
>  drivers/gpu/drm/i915/intel_drv.h  |   4 +
>  drivers/gpu/drm/i915/intel_vdsc.c | 455 ++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_dp_helper.h       |   3 +
>  include/drm/drm_dsc.h             |   2 +-
>  6 files changed, 472 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/intel_vdsc.c
> 
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 5794f10..deaf2d4 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -153,7 +153,8 @@ i915-y += dvo_ch7017.o \
>  	  intel_sdvo.o \
>  	  intel_tv.o \
>  	  vlv_dsi.o \
> -	  vlv_dsi_pll.o
> +	  vlv_dsi_pll.o \
> +	  intel_vdsc.o
>  
>  # Post-mortem debug and GPU hang state capture
>  i915-$(CONFIG_DRM_I915_CAPTURE_ERROR) += i915_gpu_error.o
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 7132f52..dc0a3c2 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -2042,6 +2042,13 @@ static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
>  			return false;
>  		}
>  	}
> +	if (intel_dp_compute_dsc_params(intel_dp, pipe_config) < 0) {
> +		DRM_ERROR("Cannot compute valid DSC parameters for Input Bpp = %d"
> +			  "Compressed BPP = %d\n",
> +			  pipe_config->pipe_bpp,
> +			  pipe_config->dsc_params.compressed_bpp);
> +		return false;
> +	}
>  	pipe_config->dsc_params.compression_enable = true;
>  	DRM_DEBUG_KMS("DP DSC computed with Input Bpp = %d "
>  		      "Compressed Bpp = %d Slice Count = %d\n",
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index b7c2652..33cc777 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1749,6 +1749,10 @@ uint16_t intel_dp_dsc_get_output_bpp(int link_clock, uint8_t lane_count,
>  uint8_t intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp, int mode_clock,
>  				     int mode_hdisplay);
>  
> +/* intel_vdsc.c */
> +int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
> +				struct intel_crtc_state *pipe_config);
> +
>  static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
>  {
>  	return ~((1 << lane_count) - 1) & 0xf;
> diff --git a/drivers/gpu/drm/i915/intel_vdsc.c b/drivers/gpu/drm/i915/intel_vdsc.c
> new file mode 100644
> index 0000000..ecd270c
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_vdsc.c
> @@ -0,0 +1,455 @@
> +/*
> + * Copyright © 2018 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Author: Gaurav K Singh <gaurav.k.singh at intel.com>
> + *         Manasi Navare <manasi.d.navare at intel.com>
> + */
> +
> +#include <drm/drmP.h>
> +#include <drm/i915_drm.h>
> +#include "i915_drv.h"
> +#include "intel_drv.h"
> +
> +enum ROW_INDEX_BPP {
> +	ROW_INDEX_6BPP = 0,
> +	ROW_INDEX_8BPP,
> +	ROW_INDEX_10BPP,
> +	ROW_INDEX_12BPP,
> +	ROW_INDEX_15BPP,
> +	MAX_ROW_INDEX
> +};
> +
> +enum COLUMN_INDEX_BPC {
> +	COLUMN_INDEX_8BPC = 0,
> +	COLUMN_INDEX_10BPC,
> +	COLUMN_INDEX_12BPC,
> +	COLUMN_INDEX_14BPC,
> +	COLUMN_INDEX_16BPC,
> +	MAX_COLUMN_INDEX
> +};
> +
> +#define DSC_SUPPORTED_VERSION_MIN		1
> +
> +/* From DSC_v1.11 spec, rc_parameter_Set syntax element typically constant */
> +static u16 rc_buf_thresh[] = {
> +	896, 1792, 2688, 3584, 4480, 5376, 6272, 6720, 7168, 7616,
> +	7744, 7872, 8000, 8064
> +};
> +
> +struct rc_parameters {
> +	u16 initial_xmit_delay;
> +	u8 first_line_bpg_offset;
> +	u16 initial_offset;
> +	u8 flatness_min_qp;
> +	u8 flatness_max_qp;
> +	u8 rc_quant_incr_limit0;
> +	u8 rc_quant_incr_limit1;
> +	struct dsc_rc_range_parameters rc_range_params[DSC_NUM_BUF_RANGES];
> +};
> +
> +/*
> + * Selected Rate Control Related Parameter Recommended Values
> + * from DSC_v1.11 spec & C Model release: DSC_model_20161212
> + */
> +static struct rc_parameters rc_params[][MAX_COLUMN_INDEX] = {
> +{
> +	/* 6BPP/8BPC */
> +	{ 768, 15, 6144, 3, 13, 11, 11, {
> +		{ 0, 4, 0 }, { 1, 6, -2 }, { 3, 8, -2 }, { 4, 8, -4 },
> +		{ 5, 9, -6 }, { 5, 9, -6 }, { 6, 9, -6 }, { 6, 10, -8 },
> +		{ 7, 11, -8 }, { 8, 12, -10 }, { 9, 12, -10 }, { 10, 12, -12 },
> +		{ 10, 12, -12 }, { 11, 12, -12 }, { 13, 14, -12 }
> +		}
> +	},
> +	/* 6BPP/10BPC */
> +	{ 768, 15, 6144, 7, 17, 15, 15, {
> +		{ 0, 8, 0 }, { 3, 10, -2 }, { 7, 12, -2 }, { 8, 12, -4 },
> +		{ 9, 13, -6 }, { 9, 13, -6 }, { 10, 13, -6 }, { 10, 14, -8 },
> +		{ 11, 15, -8 }, { 12, 16, -10 }, { 13, 16, -10 },
> +		{ 14, 16, -12 }, { 14, 16, -12 }, { 15, 16, -12 },
> +		{ 17, 18, -12 }
> +		}
> +	},
> +	/* 6BPP/12BPC */
> +	{ 768, 15, 6144, 11, 21, 19, 19, {
> +		{ 0, 12, 0 }, { 5, 14, -2 }, { 11, 16, -2 }, { 12, 16, -4 },
> +		{ 13, 17, -6 }, { 13, 17, -6 }, { 14, 17, -6 }, { 14, 18, -8 },
> +		{ 15, 19, -8 }, { 16, 20, -10 }, { 17, 20, -10 },
> +		{ 18, 20, -12 }, { 18, 20, -12 }, { 19, 20, -12 },
> +		{ 21, 22, -12 }
> +		}
> +	},
> +	/* 6BPP/14BPC */
> +	{ 768, 15, 6144, 15, 25, 23, 27, {
> +		{ 0, 16, 0 }, { 7, 18, -2 }, { 15, 20, -2 }, { 16, 20, -4 },
> +		{ 17, 21, -6 }, { 17, 21, -6 }, { 18, 21, -6 }, { 18, 22, -8 },
> +		{ 19, 23, -8 }, { 20, 24, -10 }, { 21, 24, -10 },
> +		{ 22, 24, -12 }, { 22, 24, -12 }, { 23, 24, -12 },
> +		{ 25, 26, -12 }
> +		}
> +	},
> +	/* 6BPP/16BPC */
> +	{ 768, 15, 6144, 19, 29, 27, 27, {
> +		{ 0, 20, 0 }, { 9, 22, -2 }, { 19, 24, -2 }, { 20, 24, -4 },
> +		{ 21, 25, -6 }, { 21, 25, -6 }, { 22, 25, -6 }, { 22, 26, -8 },
> +		{ 23, 27, -8 }, { 24, 28, -10 }, { 25, 28, -10 },
> +		{ 26, 28, -12 }, { 26, 28, -12 }, { 27, 28, -12 },
> +		{ 29, 30, -12 }
> +		}
> +	},
> +},
> +{
> +	/* 8BPP/8BPC */
> +	{ 512, 12, 6144, 3, 12, 11, 11, {
> +		{ 0, 4, 2 }, { 0, 4, 0 }, { 1, 5, 0 }, { 1, 6, -2 },
> +		{ 3, 7, -4 }, { 3, 7, -6 }, { 3, 7, -8 }, { 3, 8, -8 },
> +		{ 3, 9, -8 }, { 3, 10, -10 }, { 5, 11, -10 }, { 5, 12, -12 },
> +		{ 5, 13, -12 }, { 7, 13, -12 }, { 13, 15, -12 }
> +		}
> +	},
> +	/* 8BPP/10BPC */
> +	{ 512, 12, 6144, 7, 16, 15, 15, {
> +		{ 0, 4, 2 }, { 4, 8, 0 }, { 5, 9, 0 }, { 5, 10, -2 },
> +		{ 7, 11, -4 }, { 7, 11, -6 }, { 7, 11, -8 }, { 7, 12, -8 },
> +		{ 7, 13, -8 }, { 7, 14, -10 }, { 9, 15, -10 }, { 9, 16, -12 },
> +		{ 9, 17, -12 }, { 11, 17, -12 }, { 17, 19, -12 }
> +		}
> +	},
> +	/* 8BPP/12BPC */
> +	{ 512, 12, 6144, 11, 20, 19, 19, {
> +		{ 0, 12, 2 }, { 4, 12, 0 }, { 9, 13, 0 }, { 9, 14, -2 },
> +		{ 11, 15, -4 }, { 11, 15, -6 }, { 11, 15, -8 }, { 11, 16, -8 },
> +		{ 11, 17, -8 }, { 11, 18, -10 }, { 13, 19, -10 },
> +		{ 13, 20, -12 }, { 13, 21, -12 }, { 15, 21, -12 },
> +		{ 21, 23, -12 }
> +		}
> +	},
> +	/* 8BPP/14BPC */
> +	{ 512, 12, 6144, 15, 24, 23, 23, {
> +		{ 0, 12, 0 }, { 5, 13, 0 }, { 11, 15, 0 }, { 12, 17, -2 },
> +		{ 15, 19, -4 }, { 15, 19, -6 }, { 15, 19, -8 }, { 15, 20, -8 },
> +		{ 15, 21, -8 }, { 15, 22, -10 }, { 17, 22, -10 },
> +		{ 17, 23, -12 }, { 17, 23, -12 }, { 21, 24, -12 },
> +		{ 24, 25, -12 }
> +		}
> +	},
> +	/* 8BPP/16BPC */
> +	{ 512, 12, 6144, 19, 28, 27, 27, {
> +		{ 0, 12, 2 }, { 6, 14, 0 }, { 13, 17, 0 }, { 15, 20, -2 },
> +		{ 19, 23, -4 }, { 19, 23, -6 }, { 19, 23, -8 }, { 19, 24, -8 },
> +		{ 19, 25, -8 }, { 19, 26, -10 }, { 21, 26, -10 },
> +		{ 21, 27, -12 }, { 21, 27, -12 }, { 25, 28, -12 },
> +		{ 28, 29, -12 }
> +		}
> +	},
> +},
> +{
> +	/* 10BPP/8BPC */
> +	{ 410, 15, 5632, 3, 12, 11, 11, {
> +		{ 0, 3, 2 }, { 0, 4, 0 }, { 1, 5, 0 }, { 2, 6, -2 },
> +		{ 3, 7, -4 }, { 3, 7, -6 }, { 3, 7, -8 }, { 3, 8, -8 },
> +		{ 3, 9, -8 }, { 3, 9, -10 }, { 5, 10, -10 }, { 5, 10, -10 },
> +		{ 5, 11, -12 }, { 7, 11, -12 }, { 11, 12, -12 }
> +		}
> +	},
> +	/* 10BPP/10BPC */
> +	{ 410, 15, 5632, 7, 16, 15, 15, {
> +		{ 0, 7, 2 }, { 4, 8, 0 }, { 5, 9, 0 }, { 6, 10, -2 },
> +		{ 7, 11, -4 }, { 7, 11, -6 }, { 7, 11, -8 }, { 7, 12, -8 },
> +		{ 7, 13, -8 }, { 7, 13, -10 }, { 9, 14, -10 }, { 9, 14, -10 },
> +		{ 9, 15, -12 }, { 11, 15, -12 }, { 15, 16, -12 }
> +		}
> +	},
> +	/* 10BPP/12BPC */
> +	{ 410, 15, 5632, 11, 20, 19, 19, {
> +		{ 0, 11, 2 }, { 4, 12, 0 }, { 9, 13, 0 }, { 10, 14, -2 },
> +		{ 11, 15, -4 }, { 11, 15, -6 }, { 11, 15, -8 }, { 11, 16, -8 },
> +		{ 11, 17, -8 }, { 11, 17, -10 }, { 13, 18, -10 },
> +		{ 13, 18, -10 }, { 13, 19, -12 }, { 15, 19, -12 },
> +		{ 19, 20, -12 }
> +		}
> +	},
> +	/* 10BPP/14BPC */
> +	{ 410, 15, 5632, 15, 24, 23, 23, {
> +		{ 0, 11, 2 }, { 5, 13, 0 }, { 11, 15, 0 }, { 13, 18, -2 },
> +		{ 15, 19, -4 }, { 15, 19, -6 }, { 15, 19, -8 }, { 15, 20, -8 },
> +		{ 15, 21, -8 }, { 15, 21, -10 }, { 17, 22, -10 },
> +		{ 17, 22, -10 }, { 17, 23, -12 }, { 19, 23, -12 },
> +		{ 23, 24, -12 }
> +		}
> +	},
> +	/* 10BPP/16BPC */
> +	{ 410, 15, 5632, 19, 28, 27, 27, {
> +		{ 0, 11, 2 }, { 6, 14, 0 }, { 13, 17, 0 }, { 16, 20, -2 },
> +		{ 19, 23, -4 }, { 19, 23, -6 }, { 19, 23, -8 }, { 19, 24, -8 },
> +		{ 19, 25, -8 }, { 19, 25, -10 }, { 21, 26, -10 },
> +		{ 21, 26, -10 }, { 21, 27, -12 }, { 23, 27, -12 },
> +		{ 27, 28, -12 }
> +		}
> +	},
> +},
> +{
> +	/* 12BPP/8BPC */
> +	{ 341, 15, 2048, 3, 12, 11, 11, {
> +		{ 0, 2, 2 }, { 0, 4, 0 }, { 1, 5, 0 }, { 1, 6, -2 },
> +		{ 3, 7, -4 }, { 3, 7, -6 }, { 3, 7, -8 }, { 3, 8, -8 },
> +		{ 3, 9, -8 }, { 3, 10, -10 }, { 5, 11, -10 },
> +		{ 5, 12, -12 }, { 5, 13, -12 }, { 7, 13, -12 }, { 13, 15, -12 }
> +		}
> +	},
> +	/* 12BPP/10BPC */
> +	{ 341, 15, 2048, 7, 16, 15, 15, {
> +		{ 0, 2, 2 }, { 2, 5, 0 }, { 3, 7, 0 }, { 4, 8, -2 },
> +		{ 6, 9, -4 }, { 7, 10, -6 }, { 7, 11, -8 }, { 7, 12, -8 },
> +		{ 7, 13, -8 }, { 7, 14, -10 }, { 9, 15, -10 }, { 9, 16, -12 },
> +		{ 9, 17, -12 }, { 11, 17, -12 }, { 17, 19, -12 }
> +		}
> +	},
> +	/* 12BPP/12BPC */
> +	{ 341, 15, 2048, 11, 20, 19, 19, {
> +		{ 0, 6, 2 }, { 4, 9, 0 }, { 7, 11, 0 }, { 8, 12, -2 },
> +		{ 10, 13, -4 }, { 11, 14, -6 }, { 11, 15, -8 }, { 11, 16, -8 },
> +		{ 11, 17, -8 }, { 11, 18, -10 }, { 13, 19, -10 },
> +		{ 13, 20, -12 }, { 13, 21, -12 }, { 15, 21, -12 },
> +		{ 21, 23, -12 }
> +		}
> +	},
> +	/* 12BPP/14BPC */
> +	{ 341, 15, 2048, 15, 24, 23, 23, {
> +		{ 0, 6, 2 }, { 7, 10, 0 }, { 9, 13, 0 }, { 11, 16, -2 },
> +		{ 14, 17, -4 }, { 15, 18, -6 }, { 15, 19, -8 }, { 15, 20, -8 },
> +		{ 15, 20, -8 }, { 15, 21, -10 }, { 17, 21, -10 },
> +		{ 17, 21, -12 }, { 17, 21, -12 }, { 19, 22, -12 },
> +		{ 22, 23, -12 }
> +		}
> +	},
> +	/* 12BPP/16BPC */
> +	{ 341, 15, 2048, 19, 28, 27, 27, {
> +		{ 0, 6, 2 }, { 6, 11, 0 }, { 11, 15, 0 }, { 14, 18, -2 },
> +		{ 18, 21, -4 }, { 19, 22, -6 }, { 19, 23, -8 }, { 19, 24, -8 },
> +		{ 19, 24, -8 }, { 19, 25, -10 }, { 21, 25, -10 },
> +		{ 21, 25, -12 }, { 21, 25, -12 }, { 23, 26, -12 },
> +		{ 26, 27, -12 }
> +		}
> +	},
> +},
> +{
> +	/* 15BPP/8BPC */
> +	{ 273, 15, 2048, 3, 12, 11, 11, {
> +		{ 0, 0, 10 }, { 0, 1, 8 }, { 0, 1, 6 }, { 0, 2, 4 },
> +		{ 1, 2, 2 }, { 1, 3, 0 }, { 1, 3, -2 }, { 2, 4, -4 },
> +		{ 2, 5, -6 }, { 3, 5, -8 }, { 4, 6, -10 }, { 4, 7, -10 },
> +		{ 5, 7, -12 }, { 7, 8, -12 }, { 8, 9, -12 }
> +		}
> +	},
> +	/* 15BPP/10BPC */
> +	{ 273, 15, 2048, 7, 16, 15, 15, {
> +		{ 0, 2, 10 }, { 2, 5, 8 }, { 3, 5, 6 }, { 4, 6, 4 },
> +		{ 5, 6, 2 }, { 5, 7, 0 }, { 5, 7, -2 }, { 6, 8, -4 },
> +		{ 6, 9, -6 }, { 7, 9, -8 }, { 8, 10, -10 }, { 8, 11, -10 },
> +		{ 9, 11, -12 }, { 11, 12, -12 }, { 12, 13, -12 }
> +		}
> +	},
> +	/* 15BPP/12BPC */
> +	{ 273, 15, 2048, 11, 20, 19, 19, {
> +		{ 0, 4, 10 }, { 2, 7, 8 }, { 4, 9, 6 }, { 6, 11, 4 },
> +		{ 9, 11, 2 }, { 9, 11, 0 }, { 9, 12, -2 }, { 10, 12, -4 },
> +		{ 11, 13, -6 }, { 11, 13, -8 }, { 12, 14, -10 },
> +		{ 13, 15, -10 }, { 13, 15, -12 }, { 15, 16, -12 },
> +		{ 16, 17, -12 }
> +		}
> +	},
> +	/* 15BPP/14BPC */
> +	{ 273, 15, 2048, 15, 24, 23, 23, {
> +		{ 0, 4, 10 }, { 3, 8, 8 }, { 6, 11, 6 }, { 9, 14, 4 },
> +		{ 13, 15, 2 }, { 13, 15, 0 }, { 13, 16, -2 }, { 14, 16, -4 },
> +		{ 15, 17, -6 }, { 15, 17, -8 }, { 16, 18, -10 },
> +		{ 17, 19, -10 }, { 17, 19, -12 }, { 19, 20, -12 },
> +		{ 20, 21, -12 }
> +		}
> +	},
> +	/* 15BPP/16BPC */
> +	{ 273, 15, 2048, 19, 28, 27, 27, {
> +		{ 0, 4, 10 }, { 4, 9, 8 }, { 8, 13, 6 }, { 12, 17, 4 },
> +		{ 17, 19, 2 }, { 17, 20, 0 }, { 17, 20, -2 }, { 18, 20, -4 },
> +		{ 19, 21, -6 }, { 19, 21, -8 }, { 20, 22, -10 },
> +		{ 21, 23, -10 }, { 21, 23, -12 }, { 23, 24, -12 },
> +		{ 24, 25, -12 }
> +		}
> +	}
> +}
> +};
> +
> +static int get_row_index_for_rc_params(u16 compressed_bpp)
> +{
> +	switch (compressed_bpp) {
> +	case 6:
> +		return ROW_INDEX_6BPP;
> +	case 8:
> +		return ROW_INDEX_8BPP;
> +	case 10:
> +		return ROW_INDEX_10BPP;
> +	case 12:
> +		return ROW_INDEX_12BPP;
> +	case 15:
> +		return ROW_INDEX_15BPP;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int get_column_index_for_rc_params(u8 bits_per_component)
> +{
> +	switch (bits_per_component) {
> +	case 8:
> +		return COLUMN_INDEX_8BPC;
> +	case 10:
> +		return COLUMN_INDEX_10BPC;
> +	case 12:
> +		return COLUMN_INDEX_12BPC;
> +	case 14:
> +		return COLUMN_INDEX_14BPC;
> +	case 16:
> +		return COLUMN_INDEX_16BPC;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
> +					struct intel_crtc_state *pipe_config)
> +{
> +	struct drm_dsc_config *vdsc_cfg = &pipe_config->dp_dsc_cfg;
> +	u16 compressed_bpp = pipe_config->dsc_params.compressed_bpp;
> +	u8 i = 0;
> +	u8 row_index = 0;
> +	u8 column_index = 0;
> +	u8 line_buf_depth = 0;
> +
> +	vdsc_cfg->pic_width = pipe_config->base.adjusted_mode.crtc_hdisplay;
> +	vdsc_cfg->pic_height = pipe_config->base.adjusted_mode.crtc_vdisplay;
> +	vdsc_cfg->slice_width = DIV_ROUND_UP(vdsc_cfg->pic_width,
> +					     pipe_config->dsc_params.slice_count);
> +	/*
> +	 * Slice Height of 8 works for all currently available panels. So start
> +	 * with that if pic_height is an integral multiple of 8.
> +	 * Eventually add logic to try multiple slice heights.
> +	 */
> +	if (vdsc_cfg->pic_height % 8 == 0)
> +		vdsc_cfg->slice_height = 8;
> +	else if (vdsc_cfg->pic_height % 4 == 0)
> +		vdsc_cfg->slice_height = 4;
> +	else
> +		vdsc_cfg->slice_height = 2;
> +
> +	/* Values filled from DSC Sink DPCD */
> +	vdsc_cfg->dsc_version_major = (intel_dp->dsc_dpcd[DP_DSC_REV - DP_DSC_SUPPORT] &
> +				       DP_DSC_MAJOR_MASK) >> DP_DSC_MAJOR_SHIFT;
> +	vdsc_cfg->dsc_version_minor = min(DSC_SUPPORTED_VERSION_MIN,
> +					  (intel_dp->dsc_dpcd[DP_DSC_REV - DP_DSC_SUPPORT] &
> +					   DP_DSC_MINOR_MASK) >> DP_DSC_MINOR_SHIFT);
> +
> +	vdsc_cfg->convert_rgb = intel_dp->dsc_dpcd[DP_DSC_DEC_COLOR_FORMAT_CAP - DP_DSC_SUPPORT] &
> +		DP_DSC_RGB;
> +
> +	line_buf_depth = drm_dp_dsc_sink_line_buf_depth(intel_dp->dsc_dpcd);

Add a check for return value of 0

> +	if (vdsc_cfg->dsc_version_minor == 2)
> +		vdsc_cfg->line_buf_depth = (line_buf_depth == DSC_1_2_MAX_LINEBUF_DEPTH_BITS) ?
> +			DSC_1_2_MAX_LINEBUF_DEPTH_VAL : line_buf_depth;
> +	else
> +		vdsc_cfg->line_buf_depth = (line_buf_depth > DSC_1_1_MAX_LINEBUF_DEPTH_BITS) ?
> +			DSC_1_1_MAX_LINEBUF_DEPTH_BITS : line_buf_depth;
> +
> +	/* Gen 11 does not support YCbCr */
> +	vdsc_cfg->enable422 = false;
> +	/* Gen 11 does not support VBR */
> +	vdsc_cfg->vbr_enable = false;
> +	vdsc_cfg->block_pred_enable =
> +			intel_dp->dsc_dpcd[DP_DSC_BLK_PREDICTION_SUPPORT - DP_DSC_SUPPORT] &
> +		DP_DSC_BLK_PREDICTION_IS_SUPPORTED;
> +
> +	/* Gen 11 only supports integral values of bpp */
> +	vdsc_cfg->bits_per_pixel = compressed_bpp << 4;
> +	vdsc_cfg->bits_per_component = pipe_config->pipe_bpp / 3;
> +
> +	for (i = 0; i < DSC_NUM_BUF_RANGES - 1; i++) {
> +		/*
> +		 * six 0s are appended to the lsb of each threshold value
> +		 * internally in h/w.
> +		 * Only 8 bits are allowed for programming RcBufThreshold
> +		 */
> +		vdsc_cfg->rc_buf_thresh[i] = rc_buf_thresh[i] >> 6;
> +	}
> +
> +	/*
> +	 * For 6bpp, RC Buffer threshold 12 and 13 need a different value
> +	 * as per C Model
> +	 */
> +	if (compressed_bpp == 6) {
> +		vdsc_cfg->rc_buf_thresh[12] = 0x7C;
> +		vdsc_cfg->rc_buf_thresh[13] = 0x7D;
> +	}
> +
> +	row_index = get_row_index_for_rc_params(compressed_bpp);
> +	column_index =
> +		get_column_index_for_rc_params(vdsc_cfg->bits_per_component);
> +
> +	if (row_index < 0 || column_index < 0)
> +		return -EINVAL;
> +
> +	vdsc_cfg->first_line_bpg_offset =
> +		rc_params[row_index][column_index].first_line_bpg_offset;
> +	vdsc_cfg->initial_xmit_delay =
> +		rc_params[row_index][column_index].initial_xmit_delay;
> +	vdsc_cfg->initial_offset =
> +		rc_params[row_index][column_index].initial_offset;
> +	vdsc_cfg->flatness_min_qp =
> +		rc_params[row_index][column_index].flatness_min_qp;
> +	vdsc_cfg->flatness_max_qp =
> +		rc_params[row_index][column_index].flatness_max_qp;
> +	vdsc_cfg->rc_quant_incr_limit0 =
> +		rc_params[row_index][column_index].rc_quant_incr_limit0;
> +	vdsc_cfg->rc_quant_incr_limit1 =
> +		rc_params[row_index][column_index].rc_quant_incr_limit1;
> +
> +	for (i = 0; i < DSC_NUM_BUF_RANGES; i++)
> +		vdsc_cfg->rc_range_params[i] =
> +			rc_params[row_index][column_index].rc_range_params[i];
> +
> +	/*
> +	 * BitsPerComponent value determines mux_word_size:
> +	 * When BitsPerComponent is 12bpc, muxWordSize will be equal to 64 bits
> +	 * When BitsPerComponent is 8 or 10bpc, muxWordSize will be equal to
> +	 * 48 bits
> +	 */
> +	if (vdsc_cfg->bits_per_component == 8 ||
> +	    vdsc_cfg->bits_per_component == 10)
> +		vdsc_cfg->mux_word_size = DSC_MUX_WORD_SIZE_8_10_BPC;
> +	else if (vdsc_cfg->bits_per_component == 12)
> +		vdsc_cfg->mux_word_size = DSC_MUX_WORD_SIZE_12_BPC;
> +
> +	/* InitialScaleValue is a 6 bit value with 3 fractional bits (U3.3) */
> +	vdsc_cfg->initial_scale_value = (vdsc_cfg->rc_model_size << 3) /
> +		(vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset);

                        ^^^^^vdsc_cfg->rc_model_size is only defined but not getting set anywhere.
It should be set to DSC_RC_MODEL_SIZE_CONST defined in drm_dsc.h else it results into an incorrect default value.

> +
> +	return 0;
> +}
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 0cf2407..f178933 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -186,6 +186,9 @@
>  
>  #define DP_GUID				    0x030   /* 1.2 */
>  
> +#define DP_DSC_RC_PIXELS_PER_GROUP		3
> +#define DP_DSC_SCALE_DECREMENT_INTERVAL_MAX	4095

This patch in drm should be sent as a separate patch or combined with the patch
where you are defining DRM DSC parameters and constants.

Manasi

> +
>  #define DP_DSC_SUPPORT                      0x060   /* DP 1.4 */
>  # define DP_DSC_DECOMPRESSION_IS_SUPPORTED  (1 << 0)
>  
> diff --git a/include/drm/drm_dsc.h b/include/drm/drm_dsc.h
> index 4cfcd03..796c798 100644
> --- a/include/drm/drm_dsc.h
> +++ b/include/drm/drm_dsc.h
> @@ -67,7 +67,7 @@ struct dsc_rc_range_parameters {
>  	/* Max Quantization Parameters allowed for this range */
>  	u8 range_max_qp;
>  	/* Bits/group offset to apply to target for this group */
> -	u8 range_bpg_offset;
> +	s8 range_bpg_offset;
>  };
>  
>  struct drm_dsc_config {
> -- 
> 2.7.4
> 


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