[Intel-gfx] [PATCH 2/6] drm/i915: Don't use split gamma when we don't have to
Matt Roper
matthew.d.roper at intel.com
Fri Mar 29 00:16:03 UTC 2019
On Thu, Mar 28, 2019 at 11:05:01PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Using the split gamma mode when we don't have to has the annoying
> requirement of loading a linear LUT to the unused half. Instead
> let's make life simpler by switching to the 10bit gamma mode
> and duplicating each entry.
>
> This also allows us to load the software gamma LUT into the
> hardware degamma LUT, thus removing some of the buggy
> configurations we currently allow (YCbCr/limited range RGB
> + gamma LUT). We do still have other configurations that are
> also buggy, but those will need more complicated fixes
> or they just need to be rejected. Sadly GLK doesn't have
> this flexibility anymore and the degamma and gamma LUTs
> are very different so no help there.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 1 +
> drivers/gpu/drm/i915/intel_color.c | 159 +++++++++++++++--------------
> 2 files changed, 86 insertions(+), 74 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c866379a521b..eb7e93354cfe 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -10127,6 +10127,7 @@ enum skl_power_gate {
> #define PAL_PREC_SPLIT_MODE (1 << 31)
> #define PAL_PREC_AUTO_INCREMENT (1 << 15)
> #define PAL_PREC_INDEX_VALUE_MASK (0x3ff << 0)
> +#define PAL_PREC_INDEX_VALUE(x) ((x) << 0)
> #define _PAL_PREC_DATA_A 0x4A404
> #define _PAL_PREC_DATA_B 0x4AC04
> #define _PAL_PREC_DATA_C 0x4B404
> diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
> index d7c38a2bbd8f..ed4bd9bd15f5 100644
> --- a/drivers/gpu/drm/i915/intel_color.c
> +++ b/drivers/gpu/drm/i915/intel_color.c
> @@ -466,72 +466,32 @@ static void skl_color_commit(const struct intel_crtc_state *crtc_state)
> ilk_load_csc_matrix(crtc_state);
> }
>
> -static void bdw_load_degamma_lut(const struct intel_crtc_state *crtc_state)
> +static void bdw_load_lut_10(struct intel_crtc *crtc,
> + const struct drm_property_blob *blob,
> + u32 prec_index, bool duplicate)
> {
> - 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 *degamma_lut = crtc_state->base.degamma_lut;
> - u32 i, lut_size = INTEL_INFO(dev_priv)->color.degamma_lut_size;
> + const struct drm_color_lut *lut = blob->data;
> + int i, lut_size = drm_color_lut_size(blob);
> enum pipe pipe = crtc->pipe;
>
> - I915_WRITE(PREC_PAL_INDEX(pipe),
> - PAL_PREC_SPLIT_MODE | PAL_PREC_AUTO_INCREMENT);
> -
> - if (degamma_lut) {
> - const struct drm_color_lut *lut = degamma_lut->data;
> + I915_WRITE(PREC_PAL_INDEX(pipe), prec_index |
> + PAL_PREC_AUTO_INCREMENT);
>
> - for (i = 0; i < lut_size; i++)
> - I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_10(&lut[i]));
> - } else {
> + /*
> + * We advertize the split gamma sizes. When not using split
> + * gamma we just duplicate each entry.
> + *
> + * TODO: expose the full LUT to userspace
Any reason not to just do this immediately? Throwing away half the
table entries if we decide we need split mode doesn't seem any harder
than duplicating the entries when we decide we don't. The color
management kerneldoc already explicitly recommends this approach for
hardware that can support multiple gamma modes, so I don't think we need
any new ABI to handle it.
> + */
> + if (duplicate) {
> for (i = 0; i < lut_size; i++) {
> - u32 v = (i * ((1 << 10) - 1)) / (lut_size - 1);
> -
> - I915_WRITE(PREC_PAL_DATA(pipe),
> - (v << 20) | (v << 10) | v);
> + I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_10(&lut[i]));
> + I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_10(&lut[i]));
> }
> - }
> -}
> -
> -static void bdw_load_gamma_lut(const struct intel_crtc_state *crtc_state, u32 offset)
> -{
> - 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 *gamma_lut = crtc_state->base.gamma_lut;
> - u32 i, lut_size = INTEL_INFO(dev_priv)->color.gamma_lut_size;
> - enum pipe pipe = crtc->pipe;
> -
> - WARN_ON(offset & ~PAL_PREC_INDEX_VALUE_MASK);
> -
> - I915_WRITE(PREC_PAL_INDEX(pipe),
> - (offset ? PAL_PREC_SPLIT_MODE : 0) |
> - PAL_PREC_AUTO_INCREMENT |
> - offset);
> -
> - if (gamma_lut) {
> - const struct drm_color_lut *lut = gamma_lut->data;
> -
> + } else {
> for (i = 0; i < lut_size; i++)
> I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_10(&lut[i]));
> -
> - /* Program the max register to clamp values > 1.0. */
> - i = lut_size - 1;
> - I915_WRITE(PREC_PAL_GC_MAX(pipe, 0),
> - drm_color_lut_extract(lut[i].red, 16));
> - I915_WRITE(PREC_PAL_GC_MAX(pipe, 1),
> - drm_color_lut_extract(lut[i].green, 16));
> - I915_WRITE(PREC_PAL_GC_MAX(pipe, 2),
> - drm_color_lut_extract(lut[i].blue, 16));
> - } else {
> - for (i = 0; i < lut_size; i++) {
> - u32 v = (i * ((1 << 10) - 1)) / (lut_size - 1);
> -
> - I915_WRITE(PREC_PAL_DATA(pipe),
> - (v << 20) | (v << 10) | v);
> - }
> -
> - I915_WRITE(PREC_PAL_GC_MAX(pipe, 0), (1 << 16) - 1);
> - I915_WRITE(PREC_PAL_GC_MAX(pipe, 1), (1 << 16) - 1);
> - I915_WRITE(PREC_PAL_GC_MAX(pipe, 2), (1 << 16) - 1);
> }
>
> /*
> @@ -541,18 +501,43 @@ static void bdw_load_gamma_lut(const struct intel_crtc_state *crtc_state, u32 of
> I915_WRITE(PREC_PAL_INDEX(pipe), 0);
> }
>
> -/* Loads the palette/gamma unit for the CRTC on Broadwell+. */
> -static void broadwell_load_luts(const struct intel_crtc_state *crtc_state)
> +static void bdw_load_lut_10_max(struct intel_crtc *crtc,
> + const struct drm_property_blob *blob)
> {
> - 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_color_lut *lut = blob->data;
> + int i = drm_color_lut_size(blob) - 1;
> + enum pipe pipe = crtc->pipe;
>
> - if (crtc_state_is_legacy_gamma(crtc_state)) {
> + /* Program the max register to clamp values > 1.0. */
> + I915_WRITE(PREC_PAL_GC_MAX(pipe, 0),
> + drm_color_lut_extract(lut[i].red, 16));
> + I915_WRITE(PREC_PAL_GC_MAX(pipe, 1),
> + drm_color_lut_extract(lut[i].green, 16));
> + I915_WRITE(PREC_PAL_GC_MAX(pipe, 2),
> + drm_color_lut_extract(lut[i].blue, 16));
Are these the right registers to use? The "Pipe Palette and Gamma" page
of the bspec indicates we should be using PAL_EXT_GC_MAX (e.g., 0x4A420
instead of 0x4A410) for both the 10-bit and split gamma modes. I only
see PAL_GC_MAX mentioned for the interpolated gamma mode.
Matt
> +}
> +
> +static void bdw_load_luts(const struct intel_crtc_state *crtc_state)
> +{
> + struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> + const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
> + const struct drm_property_blob *degamma_lut = crtc_state->base.degamma_lut;
> +
> + if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT) {
> i9xx_load_luts(crtc_state);
> + } else if (crtc_state->gamma_mode == GAMMA_MODE_MODE_SPLIT) {
> + bdw_load_lut_10(crtc, degamma_lut, PAL_PREC_SPLIT_MODE |
> + PAL_PREC_INDEX_VALUE(0), false);
> + bdw_load_lut_10(crtc, gamma_lut, PAL_PREC_SPLIT_MODE |
> + PAL_PREC_INDEX_VALUE(512), false);
> + bdw_load_lut_10_max(crtc, gamma_lut);
> } else {
> - bdw_load_degamma_lut(crtc_state);
> - bdw_load_gamma_lut(crtc_state,
> - INTEL_INFO(dev_priv)->color.degamma_lut_size);
> + const struct drm_property_blob *blob = gamma_lut ?: degamma_lut;
> +
> + bdw_load_lut_10(crtc, blob,
> + PAL_PREC_INDEX_VALUE(0), true);
> + bdw_load_lut_10_max(crtc, blob);
> }
> }
>
> @@ -624,6 +609,9 @@ static void glk_load_degamma_lut_linear(const struct intel_crtc_state *crtc_stat
>
> static void glk_load_luts(const struct intel_crtc_state *crtc_state)
> {
> + const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
> + struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> +
> /*
> * On GLK+ both pipe CSC and degamma LUT are controlled
> * by csc_enable. Hence for the cases where the CSC is
> @@ -637,22 +625,28 @@ static void glk_load_luts(const struct intel_crtc_state *crtc_state)
> else
> glk_load_degamma_lut_linear(crtc_state);
>
> - if (crtc_state_is_legacy_gamma(crtc_state))
> + if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT) {
> i9xx_load_luts(crtc_state);
> - else
> - bdw_load_gamma_lut(crtc_state, 0);
> + } else {
> + bdw_load_lut_10(crtc, gamma_lut, PAL_PREC_INDEX_VALUE(0), false);
> + bdw_load_lut_10_max(crtc, gamma_lut);
> + }
> }
>
> static void icl_load_luts(const struct intel_crtc_state *crtc_state)
> {
> + const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
> + struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> +
> if (crtc_state->base.degamma_lut)
> glk_load_degamma_lut(crtc_state);
>
> - if (crtc_state_is_legacy_gamma(crtc_state))
> + if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT) {
> i9xx_load_luts(crtc_state);
> - else
> - /* ToDo: Add support for multi segment gamma LUT */
> - bdw_load_gamma_lut(crtc_state, 0);
> + } else {
> + bdw_load_lut_10(crtc, gamma_lut, PAL_PREC_INDEX_VALUE(0), false);
> + bdw_load_lut_10_max(crtc, gamma_lut);
> + }
> }
>
> static void cherryview_load_luts(const struct intel_crtc_state *crtc_state)
> @@ -937,8 +931,25 @@ static u32 bdw_gamma_mode(const struct intel_crtc_state *crtc_state)
> if (!crtc_state->gamma_enable ||
> crtc_state_is_legacy_gamma(crtc_state))
> return GAMMA_MODE_MODE_8BIT;
> - else
> + else if (crtc_state->base.gamma_lut &&
> + crtc_state->base.degamma_lut)
> return GAMMA_MODE_MODE_SPLIT;
> + else
> + return GAMMA_MODE_MODE_10BIT;
> +}
> +
> +static u32 bdw_csc_mode(const struct intel_crtc_state *crtc_state)
> +{
> + /*
> + * CSC comes after the LUT in degamma, RGB->YCbCr,
> + * and RGB full->limited range mode.
> + */
> + if (crtc_state->base.degamma_lut ||
> + crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB ||
> + crtc_state->limited_color_range)
> + return 0;
> +
> + return CSC_POSITION_BEFORE_GAMMA;
> }
>
> static int bdw_color_check(struct intel_crtc_state *crtc_state)
> @@ -960,7 +971,7 @@ static int bdw_color_check(struct intel_crtc_state *crtc_state)
>
> crtc_state->gamma_mode = bdw_gamma_mode(crtc_state);
>
> - crtc_state->csc_mode = 0;
> + crtc_state->csc_mode = bdw_csc_mode(crtc_state);
>
> ret = intel_color_add_affected_planes(crtc_state);
> if (ret)
> @@ -1094,7 +1105,7 @@ void intel_color_init(struct intel_crtc *crtc)
> else if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
> dev_priv->display.load_luts = glk_load_luts;
> else if (INTEL_GEN(dev_priv) >= 9 || IS_BROADWELL(dev_priv))
> - dev_priv->display.load_luts = broadwell_load_luts;
> + dev_priv->display.load_luts = bdw_load_luts;
> else
> dev_priv->display.load_luts = i9xx_load_luts;
> }
> --
> 2.19.2
>
--
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795
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