[Intel-gfx] [PATCH 4/5] drm/i915: avoid reading DP_TP_CTL twice
Lucas De Marchi
lucas.demarchi at intel.com
Wed Oct 30 01:24:47 UTC 2019
Just avoid the additional read in case DP_TP_CTL is enabled:
read it once and save the value.
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
---
drivers/gpu/drm/i915/display/intel_ddi.c | 33 ++++++++++++------------
1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 2ce998529d08..41b9b9a6772a 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4148,37 +4148,38 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
struct drm_i915_private *dev_priv =
to_i915(intel_dig_port->base.base.dev);
enum port port = intel_dig_port->base.port;
- u32 val;
+ u32 dp_tp_ctl, ddi_buf_ctl;
bool wait = false;
- if (I915_READ(intel_dp->regs.dp_tp_ctl) & DP_TP_CTL_ENABLE) {
- val = I915_READ(DDI_BUF_CTL(port));
- if (val & DDI_BUF_CTL_ENABLE) {
- val &= ~DDI_BUF_CTL_ENABLE;
- I915_WRITE(DDI_BUF_CTL(port), val);
+ dp_tp_ctl = I915_READ(intel_dp->regs.dp_tp_ctl);
+
+ if (dp_tp_ctl & DP_TP_CTL_ENABLE) {
+ ddi_buf_ctl = I915_READ(DDI_BUF_CTL(port));
+ if (ddi_buf_ctl & DDI_BUF_CTL_ENABLE) {
+ I915_WRITE(DDI_BUF_CTL(port),
+ ddi_buf_ctl & ~DDI_BUF_CTL_ENABLE);
wait = true;
}
- val = I915_READ(intel_dp->regs.dp_tp_ctl);
- val &= ~(DP_TP_CTL_ENABLE | DP_TP_CTL_LINK_TRAIN_MASK);
- val |= DP_TP_CTL_LINK_TRAIN_PAT1;
- I915_WRITE(intel_dp->regs.dp_tp_ctl, val);
+ dp_tp_ctl &= ~(DP_TP_CTL_ENABLE | DP_TP_CTL_LINK_TRAIN_MASK);
+ dp_tp_ctl |= DP_TP_CTL_LINK_TRAIN_PAT1;
+ I915_WRITE(intel_dp->regs.dp_tp_ctl, dp_tp_ctl);
POSTING_READ(intel_dp->regs.dp_tp_ctl);
if (wait)
intel_wait_ddi_buf_idle(dev_priv, port);
}
- val = DP_TP_CTL_ENABLE |
- DP_TP_CTL_LINK_TRAIN_PAT1 | DP_TP_CTL_SCRAMBLE_DISABLE;
+ dp_tp_ctl = DP_TP_CTL_ENABLE |
+ DP_TP_CTL_LINK_TRAIN_PAT1 | DP_TP_CTL_SCRAMBLE_DISABLE;
if (intel_dp->link_mst)
- val |= DP_TP_CTL_MODE_MST;
+ dp_tp_ctl |= DP_TP_CTL_MODE_MST;
else {
- val |= DP_TP_CTL_MODE_SST;
+ dp_tp_ctl |= DP_TP_CTL_MODE_SST;
if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
- val |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
+ dp_tp_ctl |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
}
- I915_WRITE(intel_dp->regs.dp_tp_ctl, val);
+ I915_WRITE(intel_dp->regs.dp_tp_ctl, dp_tp_ctl);
POSTING_READ(intel_dp->regs.dp_tp_ctl);
intel_dp->DP |= DDI_BUF_CTL_ENABLE;
--
2.23.0
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