[Intel-gfx] [PATCH] drm/i915: add LG eDP panel to quirk database

Lee, Shawn C shawn.c.lee at intel.com
Thu Sep 6 07:20:33 UTC 2018


The N value was computed by kernel driver that based on synchronous clock
mode. But only specific N value (0x8000) would be acceptable for
LG LP140WF6-SPM1 eDP panel which is running at asynchronous clock mode.
With the other N value, Tcon will enter BITS mode and display black screen.
Add this panel into quirk database and give particular N value when
calculate M/N divider.

Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Cooper Chiou <cooper.chiou at intel.com>
Cc: Matt Atwood <matthew.s.atwood at intel.com>
Signed-off-by: Lee, Shawn C <shawn.c.lee at intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c      | 10 +++++++++-
 drivers/gpu/drm/i915/intel_display.c | 16 ++++++++++------
 drivers/gpu/drm/i915/intel_display.h |  3 ++-
 drivers/gpu/drm/i915/intel_dp.c      |  8 ++++++--
 drivers/gpu/drm/i915/intel_dp_mst.c  |  2 +-
 include/drm/drm_dp_helper.h          |  1 +
 6 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 0cccbcb2d03e..a0259bbbe9df 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1258,13 +1258,18 @@ struct dpcd_quirk {
 	u8 oui[3];
 	bool is_branch;
 	u32 quirks;
+	u8 dev_id[6];
 };
 
 #define OUI(first, second, third) { (first), (second), (third) }
+#define DEVICE_ID(first, second, third, fourth, fifth, sixth) \
+	{ (first), (second), (third), (fourth), (fifth), (sixth) }
 
 static const struct dpcd_quirk dpcd_quirk_list[] = {
 	/* Analogix 7737 needs reduced M and N at HBR2 link rates */
-	{ OUI(0x00, 0x22, 0xb9), true, BIT(DP_DPCD_QUIRK_LIMITED_M_N) },
+	{ OUI(0x00, 0x22, 0xb9), true, BIT(DP_DPCD_QUIRK_LIMITED_M_N), DEVICE_ID(0, 0, 0, 0, 0, 0) },
+	/* LG LP140WF6-SPM1 eDP panel */
+	{ OUI(0x00, 0x22, 0xb9), false, BIT(DP_DPCD_QUIRK_CONSTANT_N), DEVICE_ID('s', 'i', 'v', 'a', 'r', 'T') },
 };
 
 #undef OUI
@@ -1293,6 +1298,9 @@ drm_dp_get_quirks(const struct drm_dp_dpcd_ident *ident, bool is_branch)
 		if (memcmp(quirk->oui, ident->oui, sizeof(ident->oui)) != 0)
 			continue;
 
+		if (!is_branch && memcmp(quirk->dev_id, ident->device_id, 6) != 0)
+			continue;
+
 		quirks |= quirk->quirks;
 	}
 
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index ec3e24f07486..ff01a742b054 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6465,7 +6465,7 @@ static int ironlake_fdi_compute_config(struct intel_crtc *intel_crtc,
 	pipe_config->fdi_lanes = lane;
 
 	intel_link_compute_m_n(pipe_config->pipe_bpp, lane, fdi_dotclock,
-			       link_bw, &pipe_config->fdi_m_n, false);
+			       link_bw, &pipe_config->fdi_m_n, false, false);
 
 	ret = ironlake_check_fdi_lanes(dev, intel_crtc->pipe, pipe_config);
 	if (ret == -EINVAL && pipe_config->pipe_bpp > 6*3) {
@@ -6680,7 +6680,7 @@ intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den)
 
 static void compute_m_n(unsigned int m, unsigned int n,
 			uint32_t *ret_m, uint32_t *ret_n,
-			bool reduce_m_n)
+			bool reduce_m_n, bool constant_n)
 {
 	/*
 	 * Reduce M/N as much as possible without loss in precision. Several DP
@@ -6695,7 +6695,11 @@ static void compute_m_n(unsigned int m, unsigned int n,
 		}
 	}
 
-	*ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);
+	if (constant_n)
+		*ret_n = 0x8000;
+	else
+		*ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);
+
 	*ret_m = div_u64((uint64_t) m * *ret_n, n);
 	intel_reduce_m_n_ratio(ret_m, ret_n);
 }
@@ -6704,18 +6708,18 @@ void
 intel_link_compute_m_n(int bits_per_pixel, int nlanes,
 		       int pixel_clock, int link_clock,
 		       struct intel_link_m_n *m_n,
-		       bool reduce_m_n)
+		       bool reduce_m_n, bool constant_n)
 {
 	m_n->tu = 64;
 
 	compute_m_n(bits_per_pixel * pixel_clock,
 		    link_clock * nlanes * 8,
 		    &m_n->gmch_m, &m_n->gmch_n,
-		    reduce_m_n);
+		    reduce_m_n, constant_n);
 
 	compute_m_n(pixel_clock, link_clock,
 		    &m_n->link_m, &m_n->link_n,
-		    reduce_m_n);
+		    reduce_m_n, constant_n);
 }
 
 static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/intel_display.h b/drivers/gpu/drm/i915/intel_display.h
index 43f080c6538d..dde7d73bd36d 100644
--- a/drivers/gpu/drm/i915/intel_display.h
+++ b/drivers/gpu/drm/i915/intel_display.h
@@ -379,7 +379,8 @@ struct intel_link_m_n {
 void intel_link_compute_m_n(int bpp, int nlanes,
 			    int pixel_clock, int link_clock,
 			    struct intel_link_m_n *m_n,
-			    bool reduce_m_n);
+			    bool reduce_m_n,
+			    bool constant_n);
 
 bool is_ccs_modifier(u64 modifier);
 #endif
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 436c22de33b6..95edbac24919 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2000,6 +2000,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 		to_intel_digital_connector_state(conn_state);
 	bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc,
 					   DP_DPCD_QUIRK_LIMITED_M_N);
+	bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
+					   DP_DPCD_QUIRK_CONSTANT_N);
 
 	if (HAS_PCH_SPLIT(dev_priv) && !HAS_DDI(dev_priv) && port != PORT_A)
 		pipe_config->has_pch_encoder = true;
@@ -2064,7 +2066,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 			       adjusted_mode->crtc_clock,
 			       pipe_config->port_clock,
 			       &pipe_config->dp_m_n,
-			       reduce_m_n);
+			       reduce_m_n,
+			       constant_n);
 
 	if (intel_connector->panel.downclock_mode != NULL &&
 		dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) {
@@ -2074,7 +2077,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 					       intel_connector->panel.downclock_mode->clock,
 					       pipe_config->port_clock,
 					       &pipe_config->dp_m2_n2,
-					       reduce_m_n);
+					       reduce_m_n,
+					       constant_n);
 	}
 
 	if (!HAS_DDI(dev_priv))
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 352e5216cc65..ac23982fa335 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -87,7 +87,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
 			       adjusted_mode->crtc_clock,
 			       pipe_config->port_clock,
 			       &pipe_config->dp_m_n,
-			       reduce_m_n);
+			       reduce_m_n, false);
 
 	pipe_config->dp_m_n.tu = slots;
 
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 05cc31b5db16..b1b2fd609c1c 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1266,6 +1266,7 @@ enum drm_dp_quirk {
 	 * to 16 bits.
 	 */
 	DP_DPCD_QUIRK_LIMITED_M_N,
+	DP_DPCD_QUIRK_CONSTANT_N,
 };
 
 /**
-- 
2.7.4



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