LSPCON chips can generate YCBCR outputs, if asked nicely :).
In order to generate YCBCR 4:2:0 outputs, a source must:
- send YCBCR 4:4:4 signals to LSPCON
- program color space as 4:2:0 in AVI infoframes
Whereas for YCBCR 4:4:4 outputs, the source must:
- send YCBCR 4:4:4 signals to LSPCON
- program color space as 4:4:4 in AVI infoframes
So for both 4:2:0 as well as 4:4:4 outputs, we are driving the
pipe for YCBCR 4:4:4 output, but AVI infoframe's color space
information indicates LSPCON FW to start scaling down from YCBCR
4:4:4 and generate YCBCR 4:2:0 output. As the scaling is done by
LSPCON device, we need not to reserve a scaler for 4:2:0 outputs.
V2: rebase
V3: Addressed review comments from Ville
- add enum crtc_output_format instead of bool ycbcr420
- use crtc_output_format=4:4:4 for modeset of LSPCON 4:2:0 output
cases in this way we will have YCBCR 4:4:4 framework ready (except
the ABI part)
V4: Added r-b from Maarten (for v3)
Addressed review comments from Ville:
- Do not add a non-atomic state variable to determine lspcon output.
Instead add bool in CRTC state to indicate lspcon based scaling.
V5: Addressed review comments from Ville:
- Change the state bool name from external scaling to something more
relavent.
- Keep the info and adjusted_mode structures const.
- use crtc_state instead of pipe_config.
- Push all the config change into lspcon_ycbcr420_config function.
V6: Rebase, small changes to accommodate changes in patch 2.
V7: Fixed checkpatch warnings for alignment
PS: Ignored following warnings to match the current formatting:
drm/i915: Add YCBCR 4:2:0/4:4:4 support for LSPCON
-:53: CHECK:SPACING: spaces preferred around that '<<' (ctx:VxV)
#53: FILE: drivers/gpu/drm/i915/i915_reg.h:8721:
+#define TRANS_MSA_SAMPLING_444 (2<<1)
^
-:54: CHECK:SPACING: spaces preferred around that '<<' (ctx:VxV)
#54: FILE: drivers/gpu/drm/i915/i915_reg.h:8722:
+#define TRANS_MSA_CLRSP_YCBCR (2<<3)
Cc: Ville Syrjala <ville.syrj...@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Signed-off-by: Shashank Sharma <shashank.sha...@intel.com>
---
drivers/gpu/drm/i915/i915_reg.h | 2 ++
drivers/gpu/drm/i915/intel_ddi.c | 7 +++++++
drivers/gpu/drm/i915/intel_display.c | 12 ++++++++++++
drivers/gpu/drm/i915/intel_dp.c | 4 ++++
drivers/gpu/drm/i915/intel_drv.h | 5 +++++
drivers/gpu/drm/i915/intel_lspcon.c | 26 ++++++++++++++++++++++++++
6 files changed, 56 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 33e52cc..e2dcc65 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8718,6 +8718,8 @@ enum skl_power_gate {
#define TRANS_MSA_MISC(tran) _MMIO_TRANS2(tran, _TRANSA_MSA_MISC)
#define TRANS_MSA_SYNC_CLK (1<<0)
+#define TRANS_MSA_SAMPLING_444 (2<<1)
+#define TRANS_MSA_CLRSP_YCBCR (2<<3)
#define TRANS_MSA_6_BPC (0<<5)
#define TRANS_MSA_8_BPC (1<<5)
#define TRANS_MSA_10_BPC (2<<5)
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 5fcbb924..cc7f878 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1619,6 +1619,13 @@ void intel_ddi_set_pipe_settings(const struct
intel_crtc_state *crtc_state)
break;
}
+ /*
+ * As per DP 1.2 spec section 2.3.4.3 while sending
+ * YCBCR 444 signals we should program MSA MISC1/0 fields with
+ * colorspace information. The output colorspace encoding is BT601.
+ */
+ if (crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR444)
+ temp |= TRANS_MSA_SAMPLING_444 | TRANS_MSA_CLRSP_YCBCR;
I915_WRITE(TRANS_MSA_MISC(cpu_transcoder), temp);
}
diff --git a/drivers/gpu/drm/i915/intel_display.c
b/drivers/gpu/drm/i915/intel_display.c
index f3ad411..64b36d9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7662,6 +7662,8 @@ static void intel_get_crtc_ycbcr_config(struct intel_crtc
*crtc,
struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
enum intel_output_format output = INTEL_OUTPUT_FORMAT_RGB;
+ pipe_config->lspcon_downsampling = false;
+
if (IS_BROADWELL(dev_priv) || INTEL_GEN(dev_priv) >= 9) {
u32 tmp = I915_READ(PIPEMISC(crtc->pipe));
@@ -7679,6 +7681,16 @@ static void intel_get_crtc_ycbcr_config(struct
intel_crtc *crtc,
else
output = INTEL_OUTPUT_FORMAT_YCBCR420;
} else {
+ /*
+ * Currently there is no interface defined to
+ * check user preference between RGB/YCBCR444
+ * or YCBCR420. So the only possible case for
+ * YCBCR444 usage is driving YCBCR420 output
+ * with LSPCON, when pipe is configured for
+ * YCBCR444 output and LSPCON takes care of
+ * downsampling it.
+ */
+ pipe_config->lspcon_downsampling = true;
output = INTEL_OUTPUT_FORMAT_YCBCR444;
}
}
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 4eb2fe9..c5b2d03 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1693,6 +1693,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
struct drm_display_mode *adjusted_mode =
&pipe_config->base.adjusted_mode;
struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
+ struct intel_lspcon *lspcon = enc_to_intel_lspcon(&encoder->base);
enum port port = encoder->port;
struct intel_crtc *intel_crtc = to_intel_crtc(pipe_config->base.crtc);
struct intel_connector *intel_connector = intel_dp->attached_connector;
@@ -1723,6 +1724,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
pipe_config->has_pch_encoder = true;
pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
+ if (lspcon->active)
+ lspcon_ycbcr420_config(&intel_connector->base, pipe_config);
+
pipe_config->has_drrs = false;
if (IS_G4X(dev_priv) || port == PORT_A)
pipe_config->has_audio = false;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index a0d7314..1ae0449 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -894,6 +894,9 @@ struct intel_crtc_state {
/* Output format RGB/YCBCR etc */
enum intel_output_format output_format;
+
+ /* Output down scaling is done in LSPCON device */
+ bool lspcon_downsampling;
};
struct intel_crtc {
@@ -2165,6 +2168,8 @@ void lspcon_set_infoframes(struct drm_encoder *encoder,
const struct drm_connector_state *conn_state);
bool lspcon_infoframe_enabled(struct drm_encoder *encoder,
const struct intel_crtc_state *pipe_config);
+void lspcon_ycbcr420_config(struct drm_connector *connector,
+ struct intel_crtc_state *crtc_state);
/* intel_pipe_crc.c */
int intel_pipe_crc_create(struct drm_minor *minor);
diff --git a/drivers/gpu/drm/i915/intel_lspcon.c
b/drivers/gpu/drm/i915/intel_lspcon.c
index 609ec6c..520026c 100644
--- a/drivers/gpu/drm/i915/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/intel_lspcon.c
@@ -180,6 +180,21 @@ static bool lspcon_wake_native_aux_ch(struct intel_lspcon
*lspcon)
return true;
}
+void lspcon_ycbcr420_config(struct drm_connector *connector,
+ struct intel_crtc_state *crtc_state)
+{
+ const struct drm_display_info *info = &connector->display_info;
+ const struct drm_display_mode *adjusted_mode =
+ &crtc_state->base.adjusted_mode;
+
+ if (drm_mode_is_420_only(info, adjusted_mode) &&
+ connector->ycbcr_420_allowed) {
+ crtc_state->port_clock /= 2;
+ crtc_state->output_format = INTEL_OUTPUT_FORMAT_YCBCR444;
+ crtc_state->lspcon_downsampling = true;
+ }
+}
+
static bool lspcon_probe(struct intel_lspcon *lspcon)
{
int retry;
@@ -455,6 +470,15 @@ void lspcon_set_infoframes(struct drm_encoder *encoder,
return;
}
+ if (crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR444) {
+ if (crtc_state->lspcon_downsampling)
+ frame.avi.colorspace = HDMI_COLORSPACE_YUV420;
+ else
+ frame.avi.colorspace = HDMI_COLORSPACE_YUV444;
+ } else {
+ frame.avi.colorspace = HDMI_COLORSPACE_RGB;
+ }
+
drm_hdmi_avi_infoframe_quant_range(&frame.avi, mode,
crtc_state->limited_color_range ?
HDMI_QUANTIZATION_RANGE_LIMITED :
@@ -508,6 +532,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
struct intel_lspcon *lspcon = &intel_dig_port->lspcon;
struct drm_device *dev = intel_dig_port->base.base.dev;
struct drm_i915_private *dev_priv = to_i915(dev);
+ struct drm_connector *connector = &dp->attached_connector->base;
if (!HAS_LSPCON(dev_priv)) {
DRM_ERROR("LSPCON is not supported on this platform\n");
@@ -532,6 +557,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
return false;
}
+ connector->ycbcr_420_allowed = true;
lspcon->active = true;
DRM_DEBUG_KMS("Success: LSPCON init\n");
return true;
--
2.7.4
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