Re: [PATCH 04/10] drm/i915/xe3lpd: Update pmdemand programming

["Govindapillai, Vinod" <vinod.govindapillai@intel.com>]

Hi Matt,

Probably you missed one change...

On Tue, 2024-10-08 at 15:37 -0700, Matt Atwood wrote:
> From: Matt Roper <matthew.d.roper@intel.com>
> 
> There are some minor changes to pmdemand handling on Xe3:
>  - Active scalers are no longer tracked.  We can simply skip the readout
>    and programming of this field.
>  - Active dbuf slices are no longer tracked.  We should skip the readout
>    and programming of this field and also make sure that it stays 0 in
>    our software bookkeeping so that we won't erroneously return true
>    from intel_pmdemand_needs_update() due to mismatches.
>  - Even though there aren't enough pipes to utilize them, the size of
>    the 'active pipes' field has expanded to four bits, taking over the
>    register bits previously used for dbuf slices.  Since the lower bits
>    of the mask have moved, we need to update our reads/writes to handle
>    this properly.
> 
> Bspec: 68883, 69125
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_pmdemand.c | 61 +++++++++++++------
>  drivers/gpu/drm/i915/display/intel_pmdemand.h |  4 +-
>  drivers/gpu/drm/i915/i915_reg.h               |  1 +
>  3 files changed, 45 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_pmdemand.c
> b/drivers/gpu/drm/i915/display/intel_pmdemand.c
> index ceaf9e3147da..9af2f83d3a75 100644
> --- a/drivers/gpu/drm/i915/display/intel_pmdemand.c
> +++ b/drivers/gpu/drm/i915/display/intel_pmdemand.c
> @@ -258,6 +258,7 @@ intel_pmdemand_connector_needs_update(struct intel_atomic_state *state)
>  
>  static bool intel_pmdemand_needs_update(struct intel_atomic_state *state)
>  {
> +       struct drm_i915_private *i915 = to_i915(state->base.dev);
>         const struct intel_bw_state *new_bw_state, *old_bw_state;
>         const struct intel_cdclk_state *new_cdclk_state, *old_cdclk_state;
>         const struct intel_crtc_state *new_crtc_state, *old_crtc_state;
> @@ -274,12 +275,16 @@ static bool intel_pmdemand_needs_update(struct intel_atomic_state *state)
>         new_dbuf_state = intel_atomic_get_new_dbuf_state(state);
>         old_dbuf_state = intel_atomic_get_old_dbuf_state(state);
>         if (new_dbuf_state &&
> -           (new_dbuf_state->active_pipes !=
> -            old_dbuf_state->active_pipes ||
> -            new_dbuf_state->enabled_slices !=
> -            old_dbuf_state->enabled_slices))
> +           new_dbuf_state->active_pipes != old_dbuf_state->active_pipes)
>                 return true;
>  
> +       if (DISPLAY_VER(i915) < 30) {
> +               if (new_dbuf_state &&
> +                   new_dbuf_state->enabled_slices !=
> +                   old_dbuf_state->enabled_slices)
> +                       return true;
> +       }
> +
>         new_cdclk_state = intel_atomic_get_new_cdclk_state(state);
>         old_cdclk_state = intel_atomic_get_old_cdclk_state(state);
>         if (new_cdclk_state &&
> @@ -329,8 +334,10 @@ int intel_pmdemand_atomic_check(struct intel_atomic_state *state)
>  
>         new_pmdemand_state->params.active_pipes =
>                 min_t(u8, hweight8(new_dbuf_state->active_pipes), 3);
In xe3, min could be 4  (11b for 3 pipes and 100b for 4 pipes.)

BR
vinod

> -       new_pmdemand_state->params.active_dbufs =
> -               min_t(u8, hweight8(new_dbuf_state->enabled_slices), 3);
> +
> +       if (DISPLAY_VER(i915) < 30)
> +               new_pmdemand_state->params.active_dbufs =
> +                       min_t(u8, hweight8(new_dbuf_state->enabled_slices), 3);
>  
>         new_cdclk_state = intel_atomic_get_cdclk_state(state);
>         if (IS_ERR(new_cdclk_state))
> @@ -395,27 +402,32 @@ intel_pmdemand_init_pmdemand_params(struct drm_i915_private *i915,
>  
>         reg2 = intel_de_read(i915, XELPDP_INITIATE_PMDEMAND_REQUEST(1));
>  
> -       /* Set 1*/
>         pmdemand_state->params.qclk_gv_bw =
>                 REG_FIELD_GET(XELPDP_PMDEMAND_QCLK_GV_BW_MASK, reg1);
>         pmdemand_state->params.voltage_index =
>                 REG_FIELD_GET(XELPDP_PMDEMAND_VOLTAGE_INDEX_MASK, reg1);
>         pmdemand_state->params.qclk_gv_index =
>                 REG_FIELD_GET(XELPDP_PMDEMAND_QCLK_GV_INDEX_MASK, reg1);
> -       pmdemand_state->params.active_pipes =
> -               REG_FIELD_GET(XELPDP_PMDEMAND_PIPES_MASK, reg1);
> -       pmdemand_state->params.active_dbufs =
> -               REG_FIELD_GET(XELPDP_PMDEMAND_DBUFS_MASK, reg1);
>         pmdemand_state->params.active_phys =
>                 REG_FIELD_GET(XELPDP_PMDEMAND_PHYS_MASK, reg1);
>  
> -       /* Set 2*/
>         pmdemand_state->params.cdclk_freq_mhz =
>                 REG_FIELD_GET(XELPDP_PMDEMAND_CDCLK_FREQ_MASK, reg2);
>         pmdemand_state->params.ddiclk_max =
>                 REG_FIELD_GET(XELPDP_PMDEMAND_DDICLK_FREQ_MASK, reg2);
> -       pmdemand_state->params.scalers =
> -               REG_FIELD_GET(XELPDP_PMDEMAND_SCALERS_MASK, reg2);
> +
> +       if (DISPLAY_VER(i915) >= 30) {
> +               pmdemand_state->params.active_pipes =
> +                       REG_FIELD_GET(XE3_PMDEMAND_PIPES_MASK, reg1);
> +       } else {
> +               pmdemand_state->params.active_pipes =
> +                       REG_FIELD_GET(XELPDP_PMDEMAND_PIPES_MASK, reg1);
> +               pmdemand_state->params.active_dbufs =
> +                       REG_FIELD_GET(XELPDP_PMDEMAND_DBUFS_MASK, reg1);
> +
> +               pmdemand_state->params.scalers =
> +                       REG_FIELD_GET(XELPDP_PMDEMAND_SCALERS_MASK, reg2);
> +       }
>  
>  unlock:
>         mutex_unlock(&i915->display.pmdemand.lock);
> @@ -442,6 +454,10 @@ void intel_pmdemand_program_dbuf(struct drm_i915_private *i915,
>  {
>         u32 dbufs = min_t(u32, hweight8(dbuf_slices), 3);
>  
> +       /* PM Demand only tracks active dbufs on pre-Xe3 platforms */
> +       if (DISPLAY_VER(i915) >= 30)
> +               return;
> +
>         mutex_lock(&i915->display.pmdemand.lock);
>         if (drm_WARN_ON(&i915->drm,
>                         !intel_pmdemand_check_prev_transaction(i915)))
> @@ -460,7 +476,8 @@ void intel_pmdemand_program_dbuf(struct drm_i915_private *i915,
>  }
>  
>  static void
> -intel_pmdemand_update_params(const struct intel_pmdemand_state *new,
> +intel_pmdemand_update_params(struct drm_i915_private *i915,
> +                            const struct intel_pmdemand_state *new,
>                              const struct intel_pmdemand_state *old,
>                              u32 *reg1, u32 *reg2, bool serialized)
>  {
> @@ -495,16 +512,22 @@ intel_pmdemand_update_params(const struct intel_pmdemand_state *new,
>         update_reg(reg1, qclk_gv_bw, XELPDP_PMDEMAND_QCLK_GV_BW_MASK);
>         update_reg(reg1, voltage_index, XELPDP_PMDEMAND_VOLTAGE_INDEX_MASK);
>         update_reg(reg1, qclk_gv_index, XELPDP_PMDEMAND_QCLK_GV_INDEX_MASK);
> -       update_reg(reg1, active_pipes, XELPDP_PMDEMAND_PIPES_MASK);
> -       update_reg(reg1, active_dbufs, XELPDP_PMDEMAND_DBUFS_MASK);
>         update_reg(reg1, active_phys, XELPDP_PMDEMAND_PHYS_MASK);
>  
>         /* Set 2*/
>         update_reg(reg2, cdclk_freq_mhz, XELPDP_PMDEMAND_CDCLK_FREQ_MASK);
>         update_reg(reg2, ddiclk_max, XELPDP_PMDEMAND_DDICLK_FREQ_MASK);
> -       update_reg(reg2, scalers, XELPDP_PMDEMAND_SCALERS_MASK);
>         update_reg(reg2, plls, XELPDP_PMDEMAND_PLLS_MASK);
>  
> +       if (DISPLAY_VER(i915) >= 30) {
> +               update_reg(reg1, active_pipes, XE3_PMDEMAND_PIPES_MASK);
> +       } else {
> +               update_reg(reg1, active_pipes, XELPDP_PMDEMAND_PIPES_MASK);
> +               update_reg(reg1, active_dbufs, XELPDP_PMDEMAND_DBUFS_MASK);
> +
> +               update_reg(reg2, scalers, XELPDP_PMDEMAND_SCALERS_MASK);
> +       }
> +
>  #undef update_reg
>  }
>  
> @@ -529,7 +552,7 @@ intel_pmdemand_program_params(struct drm_i915_private *i915,
>         reg2 = intel_de_read(i915, XELPDP_INITIATE_PMDEMAND_REQUEST(1));
>         mod_reg2 = reg2;
>  
> -       intel_pmdemand_update_params(new, old, &mod_reg1, &mod_reg2,
> +       intel_pmdemand_update_params(i915, new, old, &mod_reg1, &mod_reg2,
>                                      serialized);
>  
>         if (reg1 != mod_reg1) {
> diff --git a/drivers/gpu/drm/i915/display/intel_pmdemand.h
> b/drivers/gpu/drm/i915/display/intel_pmdemand.h
> index 128fd61f8f14..a1c49efdc493 100644
> --- a/drivers/gpu/drm/i915/display/intel_pmdemand.h
> +++ b/drivers/gpu/drm/i915/display/intel_pmdemand.h
> @@ -20,14 +20,14 @@ struct pmdemand_params {
>         u8 voltage_index;
>         u8 qclk_gv_index;
>         u8 active_pipes;
> -       u8 active_dbufs;
> +       u8 active_dbufs;        /* pre-Xe3 only */
>         /* Total number of non type C active phys from active_phys_mask */
>         u8 active_phys;
>         u8 plls;
>         u16 cdclk_freq_mhz;
>         /* max from ddi_clocks[] */
>         u16 ddiclk_max;
> -       u8 scalers;
> +       u8 scalers;             /* pre-Xe3 only */
>  };
>  
>  struct intel_pmdemand_state {
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 818142f5a10c..d30459f8d1cb 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2705,6 +2705,7 @@
>  #define  XELPDP_PMDEMAND_QCLK_GV_BW_MASK               REG_GENMASK(31, 16)
>  #define  XELPDP_PMDEMAND_VOLTAGE_INDEX_MASK            REG_GENMASK(14, 12)
>  #define  XELPDP_PMDEMAND_QCLK_GV_INDEX_MASK            REG_GENMASK(11, 8)
> +#define  XE3_PMDEMAND_PIPES_MASK                       REG_GENMASK(7, 4)
>  #define  XELPDP_PMDEMAND_PIPES_MASK                    REG_GENMASK(7, 6)
>  #define  XELPDP_PMDEMAND_DBUFS_MASK                    REG_GENMASK(5, 4)
>  #define  XELPDP_PMDEMAND_PHYS_MASK                     REG_GENMASK(2, 0)