On 09/06, Harry Wentland wrote: > On 2023-08-10 12:02, Melissa Wen wrote: > > From: Harry Wentland <harry.wentland@xxxxxxx> > > > > The region and segment calculation was incapable of dealing > > with regions of more than 16 segments. We first fix this. > > > > Now that we can support regions up to 256 elements we can > > define a better segment distribution for near-linear LUTs > > for our maximum of 256 HW-supported points. > > > > With these changes an "identity" LUT looks visually > > indistinguishable from bypass and allows us to use > > our 3DLUT. > > > > Have you had a chance to test whether this patch makes a > difference? I haven't had the time yet. Last time I tested there was a banding issue on plane shaper LUT PQ -> Display Native, but it seems I don't have this use case on tester anymore, so I wasn't able to double-check if the issue persist. Maybe Joshua can provide some inputs here. Something I noticed is that shaper LUTs are the only 1D LUT on DCN30 pipeline that uses cm_helper_translate_curve_to_hw_format(), all others (dpp-degamma/dpp-blend/mpc-regamma) call cm3_helper_translate_curve_*. We can drop it from this series until we get the steps to report the issue properly. Melissa > > Harry > > > Signed-off-by: Harry Wentland <harry.wentland@xxxxxxx> > > Signed-off-by: Melissa Wen <mwen@xxxxxxxxxx> > > --- > > .../amd/display/dc/dcn10/dcn10_cm_common.c | 93 +++++++++++++++---- > > 1 file changed, 75 insertions(+), 18 deletions(-) > > > > diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c > > index 3538973bd0c6..04b2e04b68f3 100644 > > --- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c > > +++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c > > @@ -349,20 +349,37 @@ bool cm_helper_translate_curve_to_hw_format(struct dc_context *ctx, > > * segment is from 2^-10 to 2^1 > > * There are less than 256 points, for optimization > > */ > > - seg_distr[0] = 3; > > - seg_distr[1] = 4; > > - seg_distr[2] = 4; > > - seg_distr[3] = 4; > > - seg_distr[4] = 4; > > - seg_distr[5] = 4; > > - seg_distr[6] = 4; > > - seg_distr[7] = 4; > > - seg_distr[8] = 4; > > - seg_distr[9] = 4; > > - seg_distr[10] = 1; > > + if (output_tf->tf == TRANSFER_FUNCTION_LINEAR) { > > + seg_distr[0] = 0; /* 2 */ > > + seg_distr[1] = 1; /* 4 */ > > + seg_distr[2] = 2; /* 4 */ > > + seg_distr[3] = 3; /* 8 */ > > + seg_distr[4] = 4; /* 16 */ > > + seg_distr[5] = 5; /* 32 */ > > + seg_distr[6] = 6; /* 64 */ > > + seg_distr[7] = 7; /* 128 */ > > + > > + region_start = -8; > > + region_end = 1; > > + } else { > > + seg_distr[0] = 3; /* 8 */ > > + seg_distr[1] = 4; /* 16 */ > > + seg_distr[2] = 4; > > + seg_distr[3] = 4; > > + seg_distr[4] = 4; > > + seg_distr[5] = 4; > > + seg_distr[6] = 4; > > + seg_distr[7] = 4; > > + seg_distr[8] = 4; > > + seg_distr[9] = 4; > > + seg_distr[10] = 1; /* 2 */ > > + /* total = 8*16 + 8 + 64 + 2 = */ > > + > > + region_start = -10; > > + region_end = 1; > > + } > > + > > > > - region_start = -10; > > - region_end = 1; > > } > > > > for (i = region_end - region_start; i < MAX_REGIONS_NUMBER ; i++) > > @@ -375,16 +392,56 @@ bool cm_helper_translate_curve_to_hw_format(struct dc_context *ctx, > > > > j = 0; > > for (k = 0; k < (region_end - region_start); k++) { > > - increment = NUMBER_SW_SEGMENTS / (1 << seg_distr[k]); > > + /* > > + * We're using an ugly-ish hack here. Our HW allows for > > + * 256 segments per region but SW_SEGMENTS is 16. > > + * SW_SEGMENTS has some undocumented relationship to > > + * the number of points in the tf_pts struct, which > > + * is 512, unlike what's suggested TRANSFER_FUNC_POINTS. > > + * > > + * In order to work past this dilemma we'll scale our > > + * increment by (1 << 4) and then do the inverse (1 >> 4) > > + * when accessing the elements in tf_pts. > > + * > > + * TODO: find a better way using SW_SEGMENTS and > > + * TRANSFER_FUNC_POINTS definitions > > + */ > > + increment = (NUMBER_SW_SEGMENTS << 4) / (1 << seg_distr[k]); > > start_index = (region_start + k + MAX_LOW_POINT) * > > NUMBER_SW_SEGMENTS; > > - for (i = start_index; i < start_index + NUMBER_SW_SEGMENTS; > > + for (i = (start_index << 4); i < (start_index << 4) + (NUMBER_SW_SEGMENTS << 4); > > i += increment) { > > + struct fixed31_32 in_plus_one, in; > > + struct fixed31_32 value, red_value, green_value, blue_value; > > + uint32_t t = i & 0xf; > > + > > if (j == hw_points - 1) > > break; > > - rgb_resulted[j].red = output_tf->tf_pts.red[i]; > > - rgb_resulted[j].green = output_tf->tf_pts.green[i]; > > - rgb_resulted[j].blue = output_tf->tf_pts.blue[i]; > > + > > + in_plus_one = output_tf->tf_pts.red[(i >> 4) + 1]; > > + in = output_tf->tf_pts.red[i >> 4]; > > + value = dc_fixpt_sub(in_plus_one, in); > > + value = dc_fixpt_shr(dc_fixpt_mul_int(value, t), 4); > > + value = dc_fixpt_add(in, value); > > + red_value = value; > > + > > + in_plus_one = output_tf->tf_pts.green[(i >> 4) + 1]; > > + in = output_tf->tf_pts.green[i >> 4]; > > + value = dc_fixpt_sub(in_plus_one, in); > > + value = dc_fixpt_shr(dc_fixpt_mul_int(value, t), 4); > > + value = dc_fixpt_add(in, value); > > + green_value = value; > > + > > + in_plus_one = output_tf->tf_pts.blue[(i >> 4) + 1]; > > + in = output_tf->tf_pts.blue[i >> 4]; > > + value = dc_fixpt_sub(in_plus_one, in); > > + value = dc_fixpt_shr(dc_fixpt_mul_int(value, t), 4); > > + value = dc_fixpt_add(in, value); > > + blue_value = value; > > + > > + rgb_resulted[j].red = red_value; > > + rgb_resulted[j].green = green_value; > > + rgb_resulted[j].blue = blue_value; > > j++; > > } > > } >