Re: [PATCH 2/2] drm/i915/psr: Set frames before SU entry for psr2

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Sep 25, 2017 at 09:10:28AM +0000, vathsala nagaraju wrote:
> On Monday 25 September 2017 02:00 PM, Jani Nikula wrote:
> 
>     On Sat, 23 Sep 2017, vathsala nagaraju <vathsala.nagaraju@intel.com> wrote:
> 
>         Set frames before SU entry value for max resync frame count of
>         dpcd register 2009, bit field 0:3.
> 
>         v2 :
>          - add macro  EDP_PSR2_FRAME_BEFORE_SU (Rodrigo)
>          - remove EDP_FRAMES_BEFORE_SU_ENTRY (Rodrigo)
>          - add check ==1 for dpcd_read call (ville)
> 
>         v3 : (Rodrigo)
>          - move macro EDP_PSR2_FRAME_BEFORE_SU after EDP_PSR2_FRAME_BEFORE_SU
>          - replace with &=
> 
>         Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>         CC: Puthikorn Voravootivat <puthik@chromium.org>
>         Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
>         Signed-off-by: Vathsala Nagaraju <vathsala.nagaraju@intel.com>
>         ---
>          drivers/gpu/drm/i915/i915_reg.h  |  2 +-
>          drivers/gpu/drm/i915/intel_psr.c | 12 ++++++++++--
>          2 files changed, 11 insertions(+), 3 deletions(-)
> 
>         diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>         index 82f36dd..b880c84 100644
>         --- a/drivers/gpu/drm/i915/i915_reg.h
>         +++ b/drivers/gpu/drm/i915/i915_reg.h
>         @@ -4047,7 +4047,7 @@ enum {
>          #define   EDP_PSR2_FRAME_BEFORE_SU_SHIFT 4
>          #define   EDP_PSR2_FRAME_BEFORE_SU_MASK        (0xf<<4)
>          #define   EDP_PSR2_IDLE_MASK           0xf
>         -#define   EDP_FRAMES_BEFORE_SU_ENTRY   (1<<4)
>         +#define EDP_PSR2_FRAME_BEFORE_SU(a) ((a) << EDP_PSR2_FRAME_BEFORE_SU_SHIFT)
> 
>     In the register definitions we use the shift values directly, not the
>     macro. That's the style we've adopted. Please stick to it.
> 
> Macro was suggested by Rodrigo.

Well, one bad review is not an excuse to ignore a good review ;)

But what Jani mentioned and he is absolutelly right is to use the shift value
directly instead the SHIFT macro, not to avoid the function-like macro that I
suggested.

In other words:

#define   EDP_PSR2_FRAME_BEFORE_SU(a) ((a) << 4)

Please also note his request on the spaces required for proper identation.

And also please address his comments on the first patch to make the defines
in total sync with DP Spec.

Thanks,
Rodrigo.

> 
> 
>     Ditto for the indent, why do you remove it?
> 
> BR, Jani.
> 
> 
>          #define EDP_PSR2_STATUS_CTL            _MMIO(0x6f940)
>          #define EDP_PSR2_STATUS_STATE_MASK     (0xf<<28)
>         diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
>         index 0a17d1f..adf7abc 100644
>         --- a/drivers/gpu/drm/i915/intel_psr.c
>         +++ b/drivers/gpu/drm/i915/intel_psr.c
>         @@ -327,6 +327,7 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
>                  */
>                 uint32_t idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
>                 uint32_t val;
>         +       uint8_t sink_latency;
> 
>                 val = idle_frames << EDP_PSR_IDLE_FRAME_SHIFT;
> 
>         @@ -334,8 +335,15 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
>                  * mesh at all with our frontbuffer tracking. And the hw alone isn't
>                  * good enough. */
>                 val |= EDP_PSR2_ENABLE |
>         -               EDP_SU_TRACK_ENABLE |
>         -               EDP_FRAMES_BEFORE_SU_ENTRY;
>         +               EDP_SU_TRACK_ENABLE;
>         +
>         +       if (drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_SYNCHRONIZATION_LATENCY,
>         +                               &sink_latency) == 1) {
>         +               sink_latency &= DP_MAX_RESYNC_FRAME_CNT_MASK;
>         +       } else {
>         +               sink_latency = 0;
>         +       }
>         +       val |= EDP_PSR2_FRAME_BEFORE_SU(sink_latency + 1);
> 
>                 if (dev_priv->vbt.psr.tp2_tp3_wakeup_time > 5)
>                         val |= EDP_PSR2_TP2_TIME_2500;
> 
> 
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