From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Apparently SKL/KBL/CFL need some manual help to get the
programmed HDMI vswing to stick. Implement the relevant
workaround (display w/a #1143).
Note that the relevant chicken bits live in a transcoder register
even though the bits affect a specific DDI port rather than a
specific transcoder. Hence we must pick the correct transcoder
register instance based on the port rather than based on the
cpu_transcoder.
Also note that for completeness I included support for DDI A/E
in the code even though we never have HDMI on those ports.
v2: CFL needs the w/a as well (Rodrigo and Art)
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Art Runyan <arthur.j.runyan@xxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_reg.h | 8 ++++++--
drivers/gpu/drm/i915/intel_ddi.c | 42 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 48 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 10e1269ad6af..2e6d0dc01dc7 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7012,8 +7012,12 @@ enum {
#define CHICKEN_TRANS_A 0x420c0
#define CHICKEN_TRANS_B 0x420c4
#define CHICKEN_TRANS(trans) _MMIO_TRANS(trans, CHICKEN_TRANS_A, CHICKEN_TRANS_B)
-#define PSR2_VSC_ENABLE_PROG_HEADER (1<<12)
-#define PSR2_ADD_VERTICAL_LINE_COUNT (1<<15)
+#define DDI_TRAINING_OVERRIDE_ENABLE (1<<19)
+#define DDI_TRAINING_OVERRIDE_VALUE (1<<18)
+#define DDIE_TRAINING_OVERRIDE_ENABLE (1<<17) /* CHICKEN_TRANS_A only */
+#define DDIE_TRAINING_OVERRIDE_VALUE (1<<16) /* CHICKEN_TRANS_A only */
+#define PSR2_ADD_VERTICAL_LINE_COUNT (1<<15)
+#define PSR2_VSC_ENABLE_PROG_HEADER (1<<12)
#define DISP_ARB_CTL _MMIO(0x45000)
#define DISP_FBC_MEMORY_WAKE (1<<31)
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 6260a882fbe4..e51559be2e3b 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2433,6 +2433,48 @@ static void intel_enable_ddi_hdmi(struct intel_encoder *encoder,
crtc_state->hdmi_high_tmds_clock_ratio,
crtc_state->hdmi_scrambling);
+ /* Display WA #1143: skl,kbl,cfl */
+ if (IS_GEN9_BC(dev_priv)) {
+ /*
+ * For some reason these chicken bits have been
+ * stuffed into a transcoder register, event though
+ * the bits affect a specific DDI port rather than
+ * a specific transcoder.
+ */
+ static const enum transcoder port_to_transcoder[] = {
+ [PORT_A] = TRANSCODER_EDP,
+ [PORT_B] = TRANSCODER_A,
+ [PORT_C] = TRANSCODER_B,
+ [PORT_D] = TRANSCODER_C,
+ [PORT_E] = TRANSCODER_A,
+ };
+ enum transcoder transcoder = port_to_transcoder[port];
+ u32 val;
+
+ val = I915_READ(CHICKEN_TRANS(transcoder));
+
+ if (port == PORT_E)
+ val |= DDIE_TRAINING_OVERRIDE_ENABLE |
+ DDIE_TRAINING_OVERRIDE_VALUE;
+ else
+ val |= DDI_TRAINING_OVERRIDE_ENABLE |
+ DDI_TRAINING_OVERRIDE_VALUE;
+
+ I915_WRITE(CHICKEN_TRANS(transcoder), val);
+ POSTING_READ(CHICKEN_TRANS(transcoder));
+
+ udelay(1);
+
+ if (port == PORT_E)
+ val &= ~(DDIE_TRAINING_OVERRIDE_ENABLE |
+ DDIE_TRAINING_OVERRIDE_VALUE);
+ else
+ val &= ~(DDI_TRAINING_OVERRIDE_ENABLE |
+ DDI_TRAINING_OVERRIDE_VALUE);
+
+ I915_WRITE(CHICKEN_TRANS(transcoder), val);
+ }
+
/* In HDMI/DVI mode, the port width, and swing/emphasis values
* are ignored so nothing special needs to be done besides
* enabling the port.
--
2.13.6
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