[Intel-gfx] [PATCH v2] drm/i915/display: Support PSR entry VSC packet to be transmitted one frame earlier

Hogander, Jouni jouni.hogander at intel.com
Wed Nov 1 09:28:51 UTC 2023


On Wed, 2023-11-01 at 10:57 +0200, Mika Kahola wrote:
> Display driver shall read DPCD 00071h[3:1] during configuration
> to get PSR setup time. This register provides the setup time
> requirement on the VSC SDP entry packet. If setup time cannot be
> met with the current timings
> (e.g., PSR setup time + other blanking requirements > blanking time),
> driver should enable sending VSC SDP one frame earlier before sending
> the capture frame.
> 
> BSpec: 69895 (PSR Entry Setup Frames 17:16)
> 
> v2: Write frames before su entry to correct register (Ville, Jouni)
>     Move frames before su entry calculation to it's own function
> (Ville, Jouni)
>     Rename PSR Entry Setup Frames register to indicate Lunarlake
> specificity (Jouni)
> 
> Signed-off-by: Mika Kahola <mika.kahola at intel.com>
> ---
>  .../drm/i915/display/intel_display_types.h    |  1 +
>  drivers/gpu/drm/i915/display/intel_psr.c      | 77 ++++++++++++++---
> --
>  drivers/gpu/drm/i915/display/intel_psr_regs.h |  2 +
>  3 files changed, 62 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 65ea37fe8cff..a0bcab6f2bec 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1710,6 +1710,7 @@ struct intel_psr {
>         u32 dc3co_exitline;
>         u32 dc3co_exit_delay;
>         struct delayed_work dc3co_work;
> +       u8 entry_setup_frames;
>  };
>  
>  struct intel_dp {
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> b/drivers/gpu/drm/i915/display/intel_psr.c
> index ecd24a0b86cb..c9e6651fb3b2 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -592,6 +592,9 @@ static void intel_psr_enable_sink(struct intel_dp
> *intel_dp)
>         if (intel_dp->psr.req_psr2_sdp_prior_scanline)
>                 dpcd_val |= DP_PSR_SU_REGION_SCANLINE_CAPTURE;
>  
> +       if (intel_dp->psr.entry_setup_frames > 0)
> +               dpcd_val |= DP_PSR_FRAME_CAPTURE;
> +
>         drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, dpcd_val);
>  
>         drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D0);
> @@ -690,6 +693,9 @@ static void hsw_activate_psr1(struct intel_dp
> *intel_dp)
>         if (DISPLAY_VER(dev_priv) >= 8)
>                 val |= EDP_PSR_CRC_ENABLE;
>  
> +       if (DISPLAY_VER(dev_priv) >= 20)
> +               val |= LNL_EDP_PSR_ENTRY_SETUP_FRAMES(intel_dp-
> >psr.entry_setup_frames);
> +
>         intel_de_rmw(dev_priv, psr_ctl_reg(dev_priv, cpu_transcoder),
>                      ~EDP_PSR_RESTORE_PSR_ACTIVE_CTX_MASK, val);
>  }
> @@ -727,11 +733,27 @@ static int psr2_block_count(struct intel_dp
> *intel_dp)
>         return psr2_block_count_lines(intel_dp) / 4;
>  }
>  
> +static u8 get_frames_before_su_entry(struct intel_dp *intel_dp)
> +{
> +       u8 frames_before_su_entry;
> +
> +       frames_before_su_entry = max_t(u8,
> +                                      intel_dp-
> >psr.sink_sync_latency + 1,
> +                                      2);
> +
> +       /* Entry setup frames must be at least 1 less than frames
> before SU entry */
> +       if (intel_dp->psr.entry_setup_frames >=
> frames_before_su_entry)
> +               frames_before_su_entry += 1;

Comment above and the code are not matching. This would match:

frames_before_su_entry = intel_dp->psr.entry_setup_frames + 1;

> +
> +       return frames_before_su_entry;
> +}
> +
>  static void hsw_activate_psr2(struct intel_dp *intel_dp)
>  {
>         struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>         enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
>         u32 val = EDP_PSR2_ENABLE;
> +       u32 psr_val = 0;
>  
>         val |=
> EDP_PSR2_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
>  
> @@ -741,7 +763,8 @@ static void hsw_activate_psr2(struct intel_dp
> *intel_dp)
>         if (DISPLAY_VER(dev_priv) >= 10 && DISPLAY_VER(dev_priv) <=
> 12)
>                 val |= EDP_Y_COORDINATE_ENABLE;
>  
> -       val |= EDP_PSR2_FRAME_BEFORE_SU(max_t(u8, intel_dp-
> >psr.sink_sync_latency + 1, 2));
> +       val |=
> EDP_PSR2_FRAME_BEFORE_SU(get_frames_before_su_entry(intel_dp));
> +
>         val |= intel_psr2_get_tp_time(intel_dp);
>  
>         if (DISPLAY_VER(dev_priv) >= 12) {
> @@ -785,6 +808,9 @@ static void hsw_activate_psr2(struct intel_dp
> *intel_dp)
>         if (intel_dp->psr.req_psr2_sdp_prior_scanline)
>                 val |= EDP_PSR2_SU_SDP_SCANLINE;
>  
> +       if (DISPLAY_VER(dev_priv) >= 20)
> +               psr_val |= LNL_EDP_PSR_ENTRY_SETUP_FRAMES(intel_dp-
> >psr.entry_setup_frames);
> +
>         if (intel_dp->psr.psr2_sel_fetch_enabled) {
>                 u32 tmp;
>  
> @@ -798,7 +824,7 @@ static void hsw_activate_psr2(struct intel_dp
> *intel_dp)
>          * PSR2 HW is incorrectly using EDP_PSR_TP1_TP3_SEL and BSpec
> is
>          * recommending keep this bit unset while PSR2 is enabled.
>          */
> -       intel_de_write(dev_priv, psr_ctl_reg(dev_priv,
> cpu_transcoder), 0);
> +       intel_de_write(dev_priv, psr_ctl_reg(dev_priv,
> cpu_transcoder), psr_val);
>  
>         intel_de_write(dev_priv, EDP_PSR2_CTL(cpu_transcoder), val);
>  }
> @@ -1066,6 +1092,36 @@ static bool _compute_psr2_wake_times(struct
> intel_dp *intel_dp,
>         return true;
>  }
>  
> +static void intel_psr_set_entry_setup_frames(struct intel_dp
> *intel_dp,

You need to convert this into

static bool intel_psr_set_entry_setup_frames(struct intel_dp *intel_dp,
						const struct
drm_display_mode *adjusted_mode)

> +                                            const struct
> drm_display_mode *adjusted_mode)
> +{
> +       struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> +       int psr_setup_time = drm_dp_psr_setup_time(intel_dp-
> >psr_dpcd);
> +
> +       intel_dp->psr.entry_setup_frames = 0;
> +
> +       if (psr_setup_time < 0) {
> +               drm_dbg_kms(&dev_priv->drm,
> +                           "PSR condition failed: Invalid PSR setup
> time (0x%02x)\n",
> +                           intel_dp->psr_dpcd[1]);
> +               return;

and return false here.

> +       }
> +
> +       if (intel_usecs_to_scanlines(adjusted_mode, psr_setup_time) >
> +           adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay
> - 1) {
> +               if (DISPLAY_VER(dev_priv) >= 20) {
> +                       intel_dp->psr.entry_setup_frames = 1;
> +                       drm_dbg_kms(&dev_priv->drm,
> +                                   "PSR setup entry frames: %d\n",
> +                                   intel_dp-
> >psr.entry_setup_frames);
> +               } else {
> +                       drm_dbg_kms(&dev_priv->drm,
> +                                   "PSR condition failed: PSR setup
> time (%d us) too long\n",
> +                                   psr_setup_time);
> +               }

and here as well.

> +       }

and return true here.

> +}
> +
>  static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
>                                     struct intel_crtc_state
> *crtc_state)
>  {
> @@ -1213,7 +1269,6 @@ void intel_psr_compute_config(struct intel_dp
> *intel_dp,
>         struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>         const struct drm_display_mode *adjusted_mode =
>                 &crtc_state->hw.adjusted_mode;
> -       int psr_setup_time;
>  
>         /*
>          * Current PSR panels don't work reliably with VRR enabled
> @@ -1242,21 +1297,7 @@ void intel_psr_compute_config(struct intel_dp
> *intel_dp,
>                 return;
>         }
>  
> -       psr_setup_time = drm_dp_psr_setup_time(intel_dp->psr_dpcd);
> -       if (psr_setup_time < 0) {
> -               drm_dbg_kms(&dev_priv->drm,
> -                           "PSR condition failed: Invalid PSR setup
> time (0x%02x)\n",
> -                           intel_dp->psr_dpcd[1]);
> -               return;
> -       }
> -
> -       if (intel_usecs_to_scanlines(adjusted_mode, psr_setup_time) >
> -           adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay
> - 1) {
> -               drm_dbg_kms(&dev_priv->drm,
> -                           "PSR condition failed: PSR setup time (%d
> us) too long\n",
> -                           psr_setup_time);
> -               return;
> -       }
> +       intel_psr_set_entry_setup_frames(intel_dp, adjusted_mode);

and have:

if (!intel_psr_set_entry_setup_frames(intel_dp, adjusted_mode))
	return;

BR,

Jouni Högander
>  
>         crtc_state->has_psr = true;
>         crtc_state->has_psr2 = intel_psr2_config_valid(intel_dp,
> crtc_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_psr_regs.h
> b/drivers/gpu/drm/i915/display/intel_psr_regs.h
> index d39951383c92..efe4306b37e0 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr_regs.h
> +++ b/drivers/gpu/drm/i915/display/intel_psr_regs.h
> @@ -35,6 +35,8 @@
>  #define  
> EDP_PSR_MIN_LINK_ENTRY_TIME_0_LINES  REG_FIELD_PREP(EDP_PSR_MIN_LINK_
> ENTRY_TIME_MASK, 3)
>  #define   EDP_PSR_MAX_SLEEP_TIME_MASK          REG_GENMASK(24, 20)
>  #define  
> EDP_PSR_MAX_SLEEP_TIME(x)            REG_FIELD_PREP(EDP_PSR_MAX_SLEEP
> _TIME_MASK, (x))
> +#define   LNL_EDP_PSR_ENTRY_SETUP_FRAMES_MASK  REG_GENMASK(17, 16)
> +#define  
> LNL_EDP_PSR_ENTRY_SETUP_FRAMES(x)    REG_FIELD_PREP(LNL_EDP_PSR_ENTRY
> _SETUP_FRAMES_MASK, (x))
>  #define   EDP_PSR_SKIP_AUX_EXIT                        REG_BIT(12)
>  #define   EDP_PSR_TP_MASK                      REG_BIT(11)
>  #define  
> EDP_PSR_TP_TP1_TP2                   REG_FIELD_PREP(EDP_PSR_TP_MASK,
> 0)



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