From 35ac28a88223d64a996535c58b8f0112118a989c Mon Sep 17 00:00:00 2001 From: Lucas De Marchi Date: Tue, 29 Oct 2019 18:24:47 -0700 Subject: [PATCH] drm/i915: avoid reading DP_TP_CTL twice MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: José Roberto de Souza Link: https://patchwork.freedesktop.org/patch/msgid/20191030012448.14937-5-lucas.demarchi@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 2f05110191a0..c91521bcf06a 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; -- 2.45.2