Re: [PATCH v5 5/9] drm/i915/tgl: Add helper function to prefer dc3co over dc5

Imre Deak
2019-08-14T09:47:08Z

On Sat, Aug 10, 2019 at 12:02:19AM +0530, Anshuman Gupta wrote:
> We need to have a S/W flag based upon which driver can switch to DC3CO.
> If it is only edp display connected and it has psr2 capability,
> then set a prefer_dc3co flag to true, which will be used to
> switch to dc3co as well as to program DC3CO PSR2 transcoder
> early exitline event.
>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Animesh Manna <animesh.manna@intel.com>
> Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_display.c | 5 +
> .../drm/i915/display/intel_display_power.c | 105 ++++++++++++++++++
> .../drm/i915/display/intel_display_power.h | 5 +
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/intel_pm.c | 2 +-
> drivers/gpu/drm/i915/intel_pm.h | 2 +
> 6 files changed, 119 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 647f49ca86ff..1ec204c14a10 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -6448,6 +6448,9 @@ static void haswell_crtc_enable(struct intel_crtc_state *pipe_config,
>
> if (WARN_ON(intel_crtc->active))
> return;
> + /* Enable PSR2 transcoder exit line */
> + if (pipe_config->has_psr2 && dev_priv->csr.prefer_dc3co)
> + tgl_enable_psr2_transcoder_exitline(pipe_config);
>
> intel_encoders_pre_pll_enable(intel_crtc, pipe_config, state);
>
> @@ -13685,6 +13688,8 @@ static int intel_atomic_check(struct drm_device *dev,
> "[modeset]" : "[fastset]");
> }
>
> + tgl_prefer_dc3co_over_dc5_check(dev_priv, state);
> +
> return 0;
>
> fail:
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
> index 167839060154..04a02c88ff93 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> @@ -18,6 +18,7 @@
> #include "intel_hotplug.h"
> #include "intel_sideband.h"
> #include "intel_tc.h"
> +#include "intel_pm.h"
>
> bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
> enum i915_power_well_id power_well_id);
> @@ -791,6 +792,110 @@ static void gen9_set_dc_state(struct drm_i915_private *dev_priv, u32 state)
> dev_priv->csr.dc_state = val & mask;
> }
>
> +void tgl_enable_psr2_transcoder_exitline(struct intel_crtc_state *cstate)
> +{
> + u32 linetime_us, val, exit_scanlines;
> + u32 crtc_vdisplay = cstate->base.adjusted_mode.crtc_vdisplay;
> + struct drm_i915_private *dev_priv = to_i915(cstate->base.crtc->dev);
> +
> + if (WARN_ON(cstate->cpu_transcoder != TRANSCODER_A))
> + return;
> +
> + linetime_us = fixed16_to_u32_round_up(intel_get_linetime_us(cstate));
> + if (WARN_ON(!linetime_us))
> + return;
> + /*
> + * DC3CO Exit time 200us B.Spec 49196
> + * PSR2 transcoder Early Exit scanlines = ROUNDUP(200 / line time) + 1
> + * Exit line event need to program above calculated scan lines before
> + * next VBLANK.
> + */
> + exit_scanlines = DIV_ROUND_UP(200, linetime_us) + 1;
> + if (WARN_ON(exit_scanlines > crtc_vdisplay))
> + return;
> +
> + exit_scanlines = crtc_vdisplay - exit_scanlines;
> + exit_scanlines <<= EXITLINE_SHIFT;
> + val = I915_READ(EXITLINE(cstate->cpu_transcoder));
> + val &= ~(EXITLINE_MASK | EXITLINE_ENABLE);
> + val |= exit_scanlines;
> + val |= EXITLINE_ENABLE;
> + I915_WRITE(EXITLINE(cstate->cpu_transcoder), val);
> +}
> +
> +static bool tgl_is_only_edp_connected(struct intel_crtc_state *crtc_state)
> +{
> + struct drm_atomic_state *state = crtc_state->base.state;
> + struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> + struct drm_connector *connector, *edp_connector = NULL;
> + struct drm_connector_state *connector_state;
> + int i;
> +
> + for_each_new_connector_in_state(state, connector, connector_state, i) {
> + if (connector_state->crtc != &crtc->base)
> + continue;
> +
> + if (connector->status == connector_status_connected &&
> + connector->connector_type != DRM_MODE_CONNECTOR_eDP)
> + return false;
> + else if (connector->connector_type == DRM_MODE_CONNECTOR_eDP &&
> + connector->status == connector_status_connected)
> + edp_connector = connector;
> + }
> +
> + if (edp_connector)
> + return true;
> +
> + return false;
> +}
> +
> +/*
> + * tgl_prefer_dc3co_over_dc5_check check whether it is worth to choose
> + * DC3CO over DC5. Currently it just check crtc psr2 capebilty and only
> + * edp display should be connected.
> + * TODO: Prefer DC3CO over DC5 only in video playback.
> + */
> +void tgl_prefer_dc3co_over_dc5_check(struct drm_i915_private *dev_priv,
> + struct intel_atomic_state *state)

One more thing here: this function will set prefer_dc3co if there is
only a PSR2 eDP output connected. However DC states will be disabled
whenever an external display is connected, so I wonder if we could just
depend on that and allow DC3CO (instead of the default DC5/6 state) from
the PSR2 enabling/disabling and page flip/idle thread functions.

> +{
> + struct intel_crtc_state *crtc_state, *mode_changed_cstate;
> + struct intel_crtc *crtc;
> + int i;
> + u32 val;
> +
> + dev_priv->csr.prefer_dc3co = false;
> +
> + if (!IS_TIGERLAKE(dev_priv))
> + return;
> +
> + if (!(dev_priv->csr.allowed_dc_mask & DC_STATE_EN_DC3CO))
> + return;
> +
> + for_each_new_intel_crtc_in_state(state, crtc, crtc_state, i) {
> + if (crtc->pipe == PIPE_A)
> + mode_changed_cstate = crtc_state;
> + if (!crtc_state->has_psr2 && crtc_state->base.active) {
> + dev_priv->csr.prefer_dc3co = false;
> + return;
> + } else if (crtc_state->has_psr2) {
> + if (tgl_is_only_edp_connected(crtc_state) &&
> + crtc_state->base.active) {
> + dev_priv->csr.prefer_dc3co = true;
> + continue;
> + } else {
> + dev_priv->csr.prefer_dc3co = false;
> + return;
> + }
> + }
> + }
> +
> + if (dev_priv->csr.prefer_dc3co) {
> + val = I915_READ(EXITLINE(mode_changed_cstate->cpu_transcoder));
> + if (!(val & EXITLINE_ENABLE))
> + mode_changed_cstate->base.mode_changed = true;
> + }
> +}
> +
> static void tgl_allow_dc3co(struct drm_i915_private *dev_priv)
> {
> gen9_set_dc_state(dev_priv, DC_STATE_EN_DC3CO);
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.h b/drivers/gpu/drm/i915/display/intel_display_power.h
> index 97f2562fc5d3..46e1bcfa490a 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.h
> @@ -12,6 +12,8 @@
>
> struct drm_i915_private;
> struct intel_encoder;
> +struct intel_crtc_state;
> +struct intel_atomic_state;
>
> enum intel_display_power_domain {
> POWER_DOMAIN_DISPLAY_CORE,
> @@ -246,6 +248,9 @@ void intel_display_power_suspend_late(struct drm_i915_private *i915);
> void intel_display_power_resume_early(struct drm_i915_private *i915);
> void intel_display_power_suspend(struct drm_i915_private *i915);
> void intel_display_power_resume(struct drm_i915_private *i915);
> +void tgl_prefer_dc3co_over_dc5_check(struct drm_i915_private *dev_priv,
> + struct intel_atomic_state *state);
> +void tgl_enable_psr2_transcoder_exitline(struct intel_crtc_state *cstate);
>
> const char *
> intel_display_power_domain_str(struct drm_i915_private *i915,
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 3cdb5bf489f2..7ca0703209a4 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -332,6 +332,7 @@ struct intel_csr {
> u32 dc_state;
> u32 allowed_dc_mask;
> intel_wakeref_t wakeref;
> + bool prefer_dc3co;
> };
>
> enum i915_cache_level {
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 780df8db2eba..634e43219164 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4584,7 +4584,7 @@ skl_wm_method2(u32 pixel_rate, u32 pipe_htotal, u32 latency,
> return ret;
> }
>
> -static uint_fixed_16_16_t
> +uint_fixed_16_16_t
> intel_get_linetime_us(const struct intel_crtc_state *crtc_state)
> {
> u32 pixel_rate;
> diff --git a/drivers/gpu/drm/i915/intel_pm.h b/drivers/gpu/drm/i915/intel_pm.h
> index e3573e1e16e3..454e92c06dff 100644
> --- a/drivers/gpu/drm/i915/intel_pm.h
> +++ b/drivers/gpu/drm/i915/intel_pm.h
> @@ -8,6 +8,7 @@
>
> #include <linux/types.h>
>
> +#include "i915_drv.h"
> #include "i915_reg.h"
>
> struct drm_device;
> @@ -76,6 +77,7 @@ u64 intel_rc6_residency_ns(struct drm_i915_private *dev_priv, i915_reg_t reg);
> u64 intel_rc6_residency_us(struct drm_i915_private *dev_priv, i915_reg_t reg);
>
> u32 intel_get_cagf(struct drm_i915_private *dev_priv, u32 rpstat1);
> +uint_fixed_16_16_t intel_get_linetime_us(const struct intel_crtc_state *cstate);
>
> unsigned long i915_chipset_val(struct drm_i915_private *dev_priv);
> unsigned long i915_mch_val(struct drm_i915_private *dev_priv);
> --
> 2.21.0
>