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drm/i915: implement Haswell DP link train sequence
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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>
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Paulo Zanoni authored and Daniel Vetter committed Oct 18, 2012
1 parent 1eb8dfe commit c19b066
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Showing 3 changed files with 81 additions and 8 deletions.
53 changes: 51 additions & 2 deletions drivers/gpu/drm/i915/intel_ddi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1108,14 +1108,23 @@ void intel_ddi_disable_pipe_clock(struct intel_crtc *intel_crtc)

void intel_ddi_pre_enable(struct intel_encoder *intel_encoder)
{
struct drm_crtc *crtc = intel_encoder->base.crtc;
struct drm_i915_private *dev_priv = crtc->dev->dev_private;
struct drm_encoder *encoder = &intel_encoder->base;
struct drm_crtc *crtc = encoder->crtc;
struct drm_i915_private *dev_priv = encoder->dev->dev_private;
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
enum port port = intel_ddi_get_encoder_port(intel_encoder);

WARN_ON(intel_crtc->ddi_pll_sel == PORT_CLK_SEL_NONE);

I915_WRITE(PORT_CLK_SEL(port), intel_crtc->ddi_pll_sel);

if (intel_encoder->type == INTEL_OUTPUT_DISPLAYPORT) {
struct intel_dp *intel_dp = enc_to_intel_dp(encoder);

intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
intel_dp_start_link_train(intel_dp);
intel_dp_complete_link_train(intel_dp);
}
}

static void intel_wait_ddi_buf_idle(struct drm_i915_private *dev_priv,
Expand Down Expand Up @@ -1210,3 +1219,43 @@ void intel_ddi_pll_init(struct drm_device *dev)
if (val & LCPLL_PLL_DISABLE)
DRM_ERROR("LCPLL is disabled\n");
}

void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder)
{
struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
struct drm_i915_private *dev_priv = encoder->dev->dev_private;
enum port port = intel_dp->port;
bool wait;
uint32_t val;

if (I915_READ(DP_TP_CTL(port)) & 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);
wait = true;
}

val = I915_READ(DP_TP_CTL(port));
val &= ~(DP_TP_CTL_ENABLE | DP_TP_CTL_LINK_TRAIN_MASK);
val |= DP_TP_CTL_LINK_TRAIN_PAT1;
I915_WRITE(DP_TP_CTL(port), val);
POSTING_READ(DP_TP_CTL(port));

if (wait)
intel_wait_ddi_buf_idle(dev_priv, port);
}

val = DP_TP_CTL_ENABLE | DP_TP_CTL_MODE_SST |
DP_TP_CTL_LINK_TRAIN_PAT1 | DP_TP_CTL_SCRAMBLE_DISABLE;
if (intel_dp->link_configuration[1] & DP_LANE_COUNT_ENHANCED_FRAME_EN)
val |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
I915_WRITE(DP_TP_CTL(port), val);
POSTING_READ(DP_TP_CTL(port));

intel_dp->DP |= DDI_BUF_CTL_ENABLE;
I915_WRITE(DDI_BUF_CTL(port), intel_dp->DP);
POSTING_READ(DDI_BUF_CTL(port));

udelay(600);
}
32 changes: 26 additions & 6 deletions drivers/gpu/drm/i915/intel_dp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -102,8 +102,6 @@ bool intel_encoder_is_pch_edp(struct drm_encoder *encoder)
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
Expand Down Expand Up @@ -1266,7 +1264,7 @@ static void ironlake_edp_pll_off(struct intel_dp *intel_dp)
}

/* 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;

Expand Down Expand Up @@ -1854,16 +1852,20 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
}

/* 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,
Expand Down Expand Up @@ -1949,7 +1951,7 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
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;
Expand Down Expand Up @@ -2035,6 +2037,24 @@ intel_dp_link_down(struct intel_dp *intel_dp)
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;

Expand Down
4 changes: 4 additions & 0 deletions drivers/gpu/drm/i915/intel_drv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -423,6 +423,9 @@ void
intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode);
extern void intel_dp_init_link_config(struct intel_dp *intel_dp);
extern void intel_dp_start_link_train(struct intel_dp *intel_dp);
extern void intel_dp_complete_link_train(struct intel_dp *intel_dp);
extern void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);
extern bool intel_dpd_is_edp(struct drm_device *dev);
extern void intel_edp_link_config(struct intel_encoder *, int *, int *);
extern int intel_edp_target_clock(struct intel_encoder *,
Expand Down Expand Up @@ -599,5 +602,6 @@ extern void intel_ddi_pre_enable(struct intel_encoder *intel_encoder);
extern void intel_ddi_post_disable(struct intel_encoder *intel_encoder);
extern void intel_ddi_put_crtc_pll(struct drm_crtc *crtc);
extern void intel_ddi_set_pipe_settings(struct drm_crtc *crtc);
extern void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder);

#endif /* __INTEL_DRV_H__ */

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