Re: [RFC 7/7] drm/i915/dp: Program vswing, pre-emphasis, test-pattern

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Hi Manasi/Jani,

Thanks for helping phy compliance design.

Added my understanding/doubts below.


On 12/12/2019 5:20 AM, Manasi Navare wrote:
Hi Animesh/Jani,

Is this the right way to force a full modeset by adding new dev_priv->dp_phy_comp?

In modeset path we disable active crtc first then initiate the modeset sequence which is causing trouble in updating phy compliance parameters in modeset path. As per phy compliance spec test-scope can request to change the following parameters,
- Test pattern
- V-swing:
- Pre-emphasis:
- Link rate:
- Lane count:

For test-pattern/v-swing/pre-emphasis, active link may not need to cut. Tried the same in the following patch series where I am skipping atomic-check, atomic-commit and write these parameters in atomic-commit-tail without touching anything else. Can you please share your thought how to handle it properly. Maybe once we are clear about what we should do in atomic_check/atomic_commit/atomic_commit_tail we can move dp_phy_comp flag to some atomic-state object.
https://patchwork.freedesktop.org/series/70300/

For Link-rate/lane-count, we need to do link-training/modeset. As per my observation the request is coming as link-compliance request, still waiting feedback from compliance team to confirm. So not handled as part dp-phy-compliance implementation.
Also its still not clear to me how this will work without actualling using the phy link rate
and lane count stored in the phy test pattern params to compute the pipe config?
Currently those only get used directly to set the link bw.

If link-compliance request is not used for link-rate/lane-count change then your point is valid. As mentioned above getting link-compliance request which is confusing and waiting confirmation from compliance team.

This can work if the phy comp runs after link layer comp but on standalone phy comp testing
this could be a problem.

Also I dont see my comment addressed where I had asked to move the below to patch 3:
+   /* Set test active flag here so userspace doesn't interrupt things */
+   intel_dp->compliance.test_active = 1;
+   dev_priv->dp_phy_comp = true;
+

Thinking of creating a separate patch for sending uevent and setting test_active flag true for intel_dp_compliance tool. The patch 3/7 will take the preparation part and acknowledge the test request. Hope it will be fine.

Regards,
Animesh

Manasi


On Sun, Nov 17, 2019 at 11:53:54PM -0800, Manasi Navare wrote:
On Fri, Nov 15, 2019 at 08:55:49PM +0530, Animesh Manna wrote:
This patch process phy compliance request by programming requested
vswing, pre-emphasis and test pattern.
Again here a slightly detailed description of where in the atomic modeset
do we process the PHY com request would be good.

The design overall looks good now, few comments below:

Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
---
  drivers/gpu/drm/i915/display/intel_ddi.c     | 14 ++++
  drivers/gpu/drm/i915/display/intel_display.c |  5 ++
  drivers/gpu/drm/i915/display/intel_dp.c      | 77 ++++++++++++++++++++
  drivers/gpu/drm/i915/display/intel_dp.h      |  2 +
  drivers/gpu/drm/i915/i915_drv.h              |  2 +
  5 files changed, 100 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 8f817de34460..c12d4ebbd352 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3700,8 +3700,17 @@ static void intel_ddi_pre_enable(struct intel_encoder *encoder,
  {
  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base);
  	enum pipe pipe = crtc->pipe;
+ if (encoder->type == INTEL_OUTPUT_DP) {
+		if (dig_port->dp.compliance.test_type ==
+		    DP_TEST_LINK_PHY_TEST_PATTERN) {
+			intel_dp_process_phy_request(&dig_port->dp);
+			return;
+		}
+	}
+
  	/*
  	 * When called from DP MST code:
  	 * - conn_state will be NULL
@@ -4147,6 +4156,11 @@ intel_ddi_pre_pll_enable(struct intel_encoder *encoder,
  	enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
  	bool is_tc_port = intel_phy_is_tc(dev_priv, phy);
+ if (encoder->type == INTEL_OUTPUT_DP)
+		if (dig_port->dp.compliance.test_type ==
+		    DP_TEST_LINK_PHY_TEST_PATTERN)
+			return;
+
  	if (is_tc_port)
  		intel_tc_port_get_link(dig_port, crtc_state->lane_count);
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index adf50c4b38ad..4ad11df55f07 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -545,6 +545,11 @@ icl_wa_scalerclkgating(struct drm_i915_private *dev_priv, enum pipe pipe,
  static bool
  needs_modeset(const struct intel_crtc_state *state)
  {
+	struct drm_i915_private *dev_priv = to_i915(state->uapi.crtc->dev);
+
+	if (dev_priv->dp_phy_comp)
+		return true;
Could you double check with Jani N if this is an acceptable solution to
foce a full modeset for a PHY compliance test?

+
  	return drm_atomic_crtc_needs_modeset(&state->uapi);
  }
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index df31278a1619..2c3d4b6c6036 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5010,14 +5010,91 @@ static inline void intel_dp_phy_pattern_update(struct intel_dp *intel_dp)
  	}
  }
+static void
+intel_dp_autotest_phy_ddi_disable(struct intel_dp *intel_dp)
+{
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	enum port port = intel_dig_port->base.port;
+	u32 ddi_buf_ctl_value, dp_tp_ctl_value, trans_ddi_func_ctl_value;
+
+	ddi_buf_ctl_value = I915_READ(DDI_BUF_CTL(port));
+	dp_tp_ctl_value = I915_READ(TGL_DP_TP_CTL(port));
+	trans_ddi_func_ctl_value = I915_READ(TRANS_DDI_FUNC_CTL(port));
+
+	ddi_buf_ctl_value        &= ~(DDI_BUF_CTL_ENABLE | DDI_PORT_WIDTH_MASK);
+	dp_tp_ctl_value          &= ~DP_TP_CTL_ENABLE;
+	trans_ddi_func_ctl_value &= ~(TRANS_DDI_FUNC_ENABLE |
+				      DDI_PORT_WIDTH_MASK);
+
+	I915_WRITE(DDI_BUF_CTL(port), ddi_buf_ctl_value);
+	I915_WRITE(TGL_DP_TP_CTL(port), dp_tp_ctl_value);
+	I915_WRITE(TRANS_DDI_FUNC_CTL(port), trans_ddi_func_ctl_value);
+}
+
+static void
+intel_dp_autotest_phy_ddi_enable(struct intel_dp *intel_dp, uint8_t lane_cnt)
+{
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	enum port port = intel_dig_port->base.port;
+	u32 ddi_buf_ctl_value, dp_tp_ctl_value, trans_ddi_func_ctl_value;
+
+	ddi_buf_ctl_value = I915_READ(DDI_BUF_CTL(port));
+	dp_tp_ctl_value = I915_READ(TGL_DP_TP_CTL(port));
+	trans_ddi_func_ctl_value = I915_READ(TRANS_DDI_FUNC_CTL(port));
+
+	ddi_buf_ctl_value        |= DDI_BUF_CTL_ENABLE |
+				    DDI_PORT_WIDTH(lane_cnt);
+	dp_tp_ctl_value          |= DP_TP_CTL_ENABLE;
+	trans_ddi_func_ctl_value |= TRANS_DDI_FUNC_ENABLE |
+				    DDI_PORT_WIDTH(lane_cnt);
+
+	I915_WRITE(TRANS_DDI_FUNC_CTL(port), trans_ddi_func_ctl_value);
+	I915_WRITE(TGL_DP_TP_CTL(port), dp_tp_ctl_value);
+	I915_WRITE(DDI_BUF_CTL(port), ddi_buf_ctl_value);
+}
+
+void intel_dp_process_phy_request(struct intel_dp *intel_dp)
+{
+	struct drm_dp_phy_test_params *data =
+		&intel_dp->compliance.test_data.phytest;
+	u8 link_status[DP_LINK_STATUS_SIZE];
+
+	if (!intel_dp_get_link_status(intel_dp, link_status)) {
+		DRM_DEBUG_KMS("failed to get link status\n");
+		return;
+	}
+
+	/* retrieve vswing & pre-emphasis setting */
+	intel_get_adjust_train(intel_dp, link_status);
+
+	intel_dp_autotest_phy_ddi_disable(intel_dp);
+
+	intel_dp_set_signal_levels(intel_dp);
+
+	intel_dp_phy_pattern_update(intel_dp);
+
+	intel_dp_autotest_phy_ddi_enable(intel_dp, data->num_lanes);
+
+	drm_dp_set_phy_test_pattern(&intel_dp->aux, data);
+}
+
  static u8 intel_dp_autotest_phy_pattern(struct intel_dp *intel_dp)
  {
  	u8 test_result = DP_TEST_NAK;
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
test_result = intel_dp_prepare_phytest(intel_dp);
  	if (test_result != DP_TEST_ACK)
  		DRM_ERROR("Phy test preparation failed\n");
+ /* Set test active flag here so userspace doesn't interrupt things */
+	intel_dp->compliance.test_active = 1;
+	dev_priv->dp_phy_comp = true;
+
This should be moved to the patch 3 I think where you handle  phy test request and
call prepare function. The same patch that handles test req can set the test active to 1.

  	return test_result;
  }
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 0d0cb692f701..b1274ecffc7f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -120,6 +120,8 @@ void intel_dp_hdr_metadata_enable(struct intel_dp *intel_dp,
  				  const struct intel_crtc_state *crtc_state,
  				  const struct drm_connector_state *conn_state);
  bool intel_digital_port_connected(struct intel_encoder *encoder);
+void intel_dp_process_phy_request(struct intel_dp *intel_dp);
+
static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
  {
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1779f600fcfb..232e0dfb9d8e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1285,6 +1285,8 @@ struct drm_i915_private {
I915_SELFTEST_DECLARE(struct i915_selftest_stash selftest;) + bool dp_phy_comp;
Not sure if this is the best way to handle the full mdoeset, could you double
check with Jani?

Other than that I think now the placement in pre_enable_dp is good.

The only other concern I have is changing link rate and lane count only happens
in set_phy_patterns where we write the test link rate and lane count
directly to the link bw set. But the driver's compute config is still configuring
the pipe and plls based on the link rate and lane count that could be
different than the test link rate/count. This might work now since you said
the link layer test is already configuring it at test params but in general
shouldnt we be using the phy->link rate and lane count if in phy compliance
also in compute_config()?

Jani, any thoughts here?

Regards
Manasi

+
  	/*
  	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
  	 * will be rejected. Instead look for a better place.
--
2.22.0

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