drm/i915: implement Haswell DP link train sequence
Previous patch "drm/i915: add basic Haswell DP link train bits"
implemented the basic structure to set the voltage levels and training
patterns. This patch adds the higher-level bits that are part of the
mode set sequence and hot plug.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index db6ef13..f6d8649 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -102,8 +102,6 @@
return is_pch_edp(intel_dp);
}
-static void intel_dp_start_link_train(struct intel_dp *intel_dp);
-static void intel_dp_complete_link_train(struct intel_dp *intel_dp);
static void intel_dp_link_down(struct intel_dp *intel_dp);
void
@@ -1266,7 +1264,7 @@
}
/* If the sink supports it, try to set the power state appropriately */
-static void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
+void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
{
int ret, i;
@@ -1854,16 +1852,20 @@
}
/* Enable corresponding port and start training pattern 1 */
-static void
+void
intel_dp_start_link_train(struct intel_dp *intel_dp)
{
- struct drm_device *dev = intel_dp->base.base.dev;
+ struct drm_encoder *encoder = &intel_dp->base.base;
+ struct drm_device *dev = encoder->dev;
int i;
uint8_t voltage;
bool clock_recovery = false;
int voltage_tries, loop_tries;
uint32_t DP = intel_dp->DP;
+ if (IS_HASWELL(dev))
+ intel_ddi_prepare_link_retrain(encoder);
+
/* Write the link configuration data */
intel_dp_aux_native_write(intel_dp, DP_LINK_BW_SET,
intel_dp->link_configuration,
@@ -1949,7 +1951,7 @@
intel_dp->DP = DP;
}
-static void
+void
intel_dp_complete_link_train(struct intel_dp *intel_dp)
{
struct drm_device *dev = intel_dp->base.base.dev;
@@ -2035,6 +2037,24 @@
struct drm_i915_private *dev_priv = dev->dev_private;
uint32_t DP = intel_dp->DP;
+ /*
+ * DDI code has a strict mode set sequence and we should try to respect
+ * it, otherwise we might hang the machine in many different ways. So we
+ * really should be disabling the port only on a complete crtc_disable
+ * sequence. This function is just called under two conditions on DDI
+ * code:
+ * - Link train failed while doing crtc_enable, and on this case we
+ * really should respect the mode set sequence and wait for a
+ * crtc_disable.
+ * - Someone turned the monitor off and intel_dp_check_link_status
+ * called us. We don't need to disable the whole port on this case, so
+ * when someone turns the monitor on again,
+ * intel_ddi_prepare_link_retrain will take care of redoing the link
+ * train.
+ */
+ if (IS_HASWELL(dev))
+ return;
+
if (WARN_ON((I915_READ(intel_dp->output_reg) & DP_PORT_EN) == 0))
return;