[PATCH 1/4] [v3] drm/i915/color: fix broken gamma state-checker during boot

Swati Sharma
2019-10-09T07:05:02Z

Premature gamma lut prepration and loading which was getting
reflected in first modeset causing different colors on
screen during boot.

Issue: In BIOS, gamma is disabled by default. However, legacy read_luts()
was setting crtc_state->base.gamma_lut and gamma_lut was programmed
with junk values which led to visual artifacts (different
colored screens instead of usual black during boot).

Fix: Calling read_luts() only when gamma is enabled which will happen
after first modeset.

This fix is independent from the revert 1b8588741fdc ("Revert
"drm/i915/color: Extract icl_read_luts()"") and should fix different colors
on screen in legacy platforms too.

v2:
-Added gamma_enable checks inside read_luts() [Ville/Jani N]
-Corrected gamma enable check for CHV [Ville]

v3:
-Added check in ilk_read_luts() [Ville]
-Simplified gamma enable check for CHV [Ville]

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111809
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111885
Tested-by: Jani Saarinen <jani.saarinen@intel.com>
Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
---
drivers/gpu/drm/i915/display/intel_color.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
index 9ab34902663e..08d020d4da35 100644
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -1613,6 +1613,9 @@ i9xx_read_lut_8(const struct intel_crtc_state *crtc_state)

static void i9xx_read_luts(struct intel_crtc_state *crtc_state)
{
+ if (!crtc_state->gamma_enable)
+ return;
+
crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state);
}

@@ -1659,6 +1662,9 @@ i965_read_lut_10p6(const struct intel_crtc_state *crtc_state)

static void i965_read_luts(struct intel_crtc_state *crtc_state)
{
+ if (!crtc_state->gamma_enable)
+ return;
+
if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state);
else
@@ -1701,10 +1707,10 @@ chv_read_cgm_lut(const struct intel_crtc_state *crtc_state)

static void chv_read_luts(struct intel_crtc_state *crtc_state)
{
- if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
- crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state);
- else
+ if (crtc_state->cgm_mode & CGM_PIPE_MODE_GAMMA)
crtc_state->base.gamma_lut = chv_read_cgm_lut(crtc_state);
+ else
+ i965_read_luts(crtc_state);
}

static struct drm_property_blob *
@@ -1742,6 +1748,12 @@ ilk_read_lut_10(const struct intel_crtc_state *crtc_state)

static void ilk_read_luts(struct intel_crtc_state *crtc_state)
{
+ if (!crtc_state->gamma_enable)
+ return;
+
+ if ((crtc_state->csc_mode & CSC_POSITION_BEFORE_GAMMA) == 0)
+ return;
+
if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state);
else
@@ -1788,6 +1800,9 @@ glk_read_lut_10(const struct intel_crtc_state *crtc_state, u32 prec_index)

static void glk_read_luts(struct intel_crtc_state *crtc_state)
{
+ if (!crtc_state->gamma_enable)
+ return;
+
if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state);
else
--
2.23.0