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drm/i915/icl: Add Multi-segmented gamma support 

ICL introduces a new gamma correction mode in display engine, called
multi-segmented-gamma mode. This mode allows users to program the
darker region of the gamma curve with sueprfine precision. An
example use case for this is HDR curves (like PQ ST-2084).

If we plot a gamma correction curve from value range between 0.0 to 1.0,
ICL's multi-segment has 3 different sections:
- superfine segment: 9 values, ranges between 0 - 1/(128 * 256)
- fine segment: 257 values, ranges between 0 - 1/(128)
- corase segment: 257 values, ranges between 0 - 1

This patch:
- Changes gamma LUTs size for ICL/GEN11 to 262144 entries (8 * 128 * 256),
  so that userspace can program with highest precision supported.
- Changes default gamma mode (non-legacy) to multi-segmented-gamma mode.
- Adds functions to program/detect multi-segment gamma.

V2: Addressed review comments from Ville
    - separate function for superfine and fine segments.
    - remove enum for segments.
    - reuse last entry of the LUT as gc_max value.
    - replace if() ....cond with switch...case in icl_load_luts.
    - add an entry variable, instead of 'word'

V3: Addressed review comments from Ville
    - extra newline
    - s/entry/color/
    - remove LUT size checks
    - program ilk_lut_12p4_ldw value before ilk_lut_12p4_udw
    - Change the comments in description of fine and coarse segments,
      and try to make more sense.
    - use 8 * 128 instead of 1024
    - add 1 entry in LUT for GCMAX

V4: Addressed review comments from Ville
    - Remove unused macro
    - missing shift entry in blue
    - pick correct entry for GCMAX
    - Added Ville's R-B
Note: Tested and confirmed the programming sequence of odd/even
registers in the HW. The correct sequence should be:
	ilk_lut_12p4_udw
	ilk_lut_12p4_ldw

v5: Addressed Ville's review comments and renamed odd/even register
helpers to be more consistent with the values.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1560321900-18318-5-git-send-email-uma.shankar@intel.com
This commit is contained in:
Shashank Sharma 2019-06-12 12:15:00 +05:30 committed by Maarten Lankhorst
parent eec0778ec4
commit 02ae8ba966
2 changed files with 123 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/gpu/drm/i915/i915_pci.c
View File

@ -747,7 +747,7 @@ static const struct intel_device_info intel_cannonlake_info = {
GEN(11), \
.ddb_size = 2048, \
.has_logical_ring_elsq = 1, \
.color = { .degamma_lut_size = 33, .gamma_lut_size = 1024 }
.color = { .degamma_lut_size = 33, .gamma_lut_size = 262145 }
static const struct intel_device_info intel_icelake_11_info = {
GEN11_FEATURES,

126
drivers/gpu/drm/i915/intel_color.c
View File

@ -41,6 +41,7 @@
#define CTM_COEFF_ABS(coeff) ((coeff) & (CTM_COEFF_SIGN - 1))
#define LEGACY_LUT_LENGTH 256
/*
* Extract the CSC coefficient from a CTM coefficient (in U32.32 fixed point
* format). This macro takes the coefficient we want transformed and the
@ -767,6 +768,116 @@ static void glk_load_luts(const struct intel_crtc_state *crtc_state)
}
}
/* ilk+ "12.4" interpolated format (high 10 bits) */
static u32 ilk_lut_12p4_udw(const struct drm_color_lut *color)
{
return (color->red >> 6) << 20 | (color->green >> 6) << 10 |
(color->blue >> 6);
}
/* ilk+ "12.4" interpolated format (low 6 bits) */
static u32 ilk_lut_12p4_ldw(const struct drm_color_lut *color)
{
return (color->red & 0x3f) << 24 | (color->green & 0x3f) << 14 |
(color->blue & 0x3f) << 4;
}
static void
icl_load_gcmax(const struct intel_crtc_state *crtc_state,
const struct drm_color_lut *color)
{
struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
enum pipe pipe = crtc->pipe;
/* Fixme: LUT entries are 16 bit only, so we can prog 0xFFFF max */
I915_WRITE(PREC_PAL_GC_MAX(pipe, 0), color->red);
I915_WRITE(PREC_PAL_GC_MAX(pipe, 1), color->green);
I915_WRITE(PREC_PAL_GC_MAX(pipe, 2), color->blue);
}
static void
icl_program_gamma_superfine_segment(const struct intel_crtc_state *crtc_state)
{
struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
const struct drm_property_blob *blob = crtc_state->base.gamma_lut;
const struct drm_color_lut *lut = blob->data;
enum pipe pipe = crtc->pipe;
u32 i;
/*
* Every entry in the multi-segment LUT is corresponding to a superfine
* segment step which is 1/(8 * 128 * 256).
*
* Superfine segment has 9 entries, corresponding to values
* 0, 1/(8 * 128 * 256), 2/(8 * 128 * 256) .... 8/(8 * 128 * 256).
*/
I915_WRITE(PREC_PAL_MULTI_SEG_INDEX(pipe), PAL_PREC_AUTO_INCREMENT);
for (i = 0; i < 9; i++) {
const struct drm_color_lut *entry = &lut[i];
I915_WRITE(PREC_PAL_MULTI_SEG_DATA(pipe),
ilk_lut_12p4_ldw(entry));
I915_WRITE(PREC_PAL_MULTI_SEG_DATA(pipe),
ilk_lut_12p4_udw(entry));
}
}
static void
icl_program_gamma_multi_segment(const struct intel_crtc_state *crtc_state)
{
struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
const struct drm_property_blob *blob = crtc_state->base.gamma_lut;
const struct drm_color_lut *lut = blob->data;
const struct drm_color_lut *entry;
enum pipe pipe = crtc->pipe;
u32 i;
/*
*
* Program Fine segment (let's call it seg2)...
*
* Fine segment's step is 1/(128 * 256) ie 1/(128 * 256), 2/(128*256)
* ... 256/(128*256). So in order to program fine segment of LUT we
* need to pick every 8'th entry in LUT, and program 256 indexes.
*
* PAL_PREC_INDEX[0] and PAL_PREC_INDEX[1] map to seg2[1],
* with seg2[0] being unused by the hardware.
*/
I915_WRITE(PREC_PAL_INDEX(pipe), PAL_PREC_AUTO_INCREMENT);
for (i = 1; i < 257; i++) {
entry = &lut[i * 8];
I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_ldw(entry));
I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_udw(entry));
}
/*
* Program Coarse segment (let's call it seg3)...
*
* Coarse segment's starts from index 0 and it's step is 1/256 ie 0,
* 1/256, 2/256 ...256/256. As per the description of each entry in LUT
* above, we need to pick every (8 * 128)th entry in LUT, and
* program 256 of those.
*
* Spec is not very clear about if entries seg3[0] and seg3[1] are
* being used or not, but we still need to program these to advance
* the index.
*/
for (i = 0; i < 256; i++) {
entry = &lut[i * 8 * 128];
I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_ldw(entry));
I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_udw(entry));
}
/* The last entry in the LUT is to be programmed in GCMAX */
entry = &lut[256 * 8 * 128];
icl_load_gcmax(crtc_state, entry);
ivb_load_lut_ext_max(crtc);
}
static void icl_load_luts(const struct intel_crtc_state *crtc_state)
{
const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
@ -775,10 +886,17 @@ static void icl_load_luts(const struct intel_crtc_state *crtc_state)
if (crtc_state->base.degamma_lut)
glk_load_degamma_lut(crtc_state);
if ((crtc_state->gamma_mode & GAMMA_MODE_MODE_MASK) ==
GAMMA_MODE_MODE_8BIT) {
switch (crtc_state->gamma_mode & GAMMA_MODE_MODE_MASK) {
case GAMMA_MODE_MODE_8BIT:
i9xx_load_luts(crtc_state);
} else {
break;
case GAMMA_MODE_MODE_12BIT_MULTI_SEGMENTED:
icl_program_gamma_superfine_segment(crtc_state);
icl_program_gamma_multi_segment(crtc_state);
break;
default:
bdw_load_lut_10(crtc, gamma_lut, PAL_PREC_INDEX_VALUE(0));
ivb_load_lut_ext_max(crtc);
}
@ -1219,7 +1337,7 @@ static u32 icl_gamma_mode(const struct intel_crtc_state *crtc_state)
crtc_state_is_legacy_gamma(crtc_state))
gamma_mode |= GAMMA_MODE_MODE_8BIT;
else
gamma_mode |= GAMMA_MODE_MODE_10BIT;
gamma_mode |= GAMMA_MODE_MODE_12BIT_MULTI_SEGMENTED;
return gamma_mode;
}