Based on the platform, Bspec expects us to wait or poll with
timeout for DDI BUF IDLE bit to be set to 0 (non idle) or get active
after enabling DDI_BUF_CTL.
v2:
* Based on platform, fixed delay or poll (Ville)
* Use a helper to do this (Imre, Ville)
v3:
* Add a new function _active for DDI BUF CTL to be non idle (Ville)
v4:
* Use the timeout for GLK (Ville)
v5:
* Add bspec quote, change timeout to 500us (Ville)
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_ddi.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index a7de1344db69..4f89ad90ab07 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -1195,6 +1195,21 @@ static void intel_wait_ddi_buf_idle(struct drm_i915_private *dev_priv,
port_name(port));
}
+static void intel_wait_ddi_buf_active(struct drm_i915_private *dev_priv,
+ enum port port)
+{
+ /* Wait > 518 usecs for DDI_BUF_CTL to be non idle */
+ if (INTEL_GEN(dev_priv) < 10 && !IS_GEMINILAKE(dev_priv)) {
+ usleep_range(518, 1000);
+ return;
+ }
+
+ if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
+ DDI_BUF_IS_IDLE), 500))
+ drm_err(&dev_priv->drm, "Timeout waiting for DDI BUF %c to get active\n",
+ port_name(port));
+}
+
static u32 hsw_pll_to_ddi_pll_sel(const struct intel_shared_dpll *pll)
{
switch (pll->info->id) {
@@ -4019,7 +4034,7 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
- udelay(600);
+ intel_wait_ddi_buf_active(dev_priv, port);
}
static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
--
2.19.1
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