On Tue, Aug 05, 2014 at 11:15:53PM +0530, Gajanan Bhat wrote:
> Modify drain latency computation to use it for any plane. Same function can be
> used for primary, cursor and sprite planes.
> 
> v2: Adressed review comments by Imre and Ville.
>     - Moved clock round up in separate patch
>     - Added WARN check for clock and pixel size
>     - Simplified bit masking
>     - Use cursor_base instead of reg read
> 
> Signed-off-by: Gajanan Bhat <gajanan.b...@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h |    1 +
>  drivers/gpu/drm/i915/intel_pm.c |   88 
> +++++++++++++++++++++++----------------
>  2 files changed, 52 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index d75bed8..55f159d 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3904,6 +3904,7 @@ enum punit_power_well {
>  #define DDL_PLANE_PRECISION_64               (1<<7)
>  #define DDL_PLANE_PRECISION_32               (0<<7)
>  #define DDL_PLANE_SHIFT                      0
> +#define DRAIN_LATENCY_MASK           0x7f
>  
>  /* FIFO watermark sizes etc */
>  #define G4X_FIFO_LINE_SIZE   64
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 3544de0..ea64675 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -1271,33 +1271,24 @@ static bool g4x_compute_srwm(struct drm_device *dev,
>                             display, cursor);
>  }
>  
> -static bool vlv_compute_drain_latency(struct drm_device *dev,
> -                                  int plane,
> -                                  int *plane_prec_mult,
> -                                  int *plane_dl,
> -                                  int *cursor_prec_mult,
> -                                  int *cursor_dl)
> +static bool vlv_compute_drain_latency(struct drm_crtc *crtc,
> +                                   int pixel_size,
> +                                   int *prec_mult,
> +                                   int *drain_latency)
>  {
> -     struct drm_crtc *crtc;
> -     int clock, pixel_size;
>       int entries;
> +     int clock = to_intel_crtc(crtc)->config.adjusted_mode.crtc_clock;
>  
> -     crtc = intel_get_crtc_for_plane(dev, plane);
> -     if (!intel_crtc_active(crtc))
> +     if (WARN(clock == 0, "Pixel clock is zero!\n"))
>               return false;
>  
> -     clock = to_intel_crtc(crtc)->config.adjusted_mode.crtc_clock;
> -     pixel_size = crtc->primary->fb->bits_per_pixel / 8;     /* BPP */
> +     if (WARN(pixel_size == 0, "Pixel size is zero!\n"))
> +             return false;
>  
>       entries = (clock / 1000) * pixel_size;
> -     *plane_prec_mult = (entries > 128) ?
> -             DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
> -     *plane_dl = (64 * (*plane_prec_mult) * 4) / entries;
> -
> -     entries = (clock / 1000) * 4;   /* BPP is always 4 for cursor */
> -     *cursor_prec_mult = (entries > 128) ?
> -             DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
> -     *cursor_dl = (64 * (*cursor_prec_mult) * 4) / entries;
> +     *prec_mult = (entries > 128) ? DRAIN_LATENCY_PRECISION_64 :
> +                                    DRAIN_LATENCY_PRECISION_32;
> +     *drain_latency = (64 * (*prec_mult) * 4) / entries;
>  
>       return true;
>  }
> @@ -1312,24 +1303,47 @@ static bool vlv_compute_drain_latency(struct 
> drm_device *dev,
>  
>  static void vlv_update_drain_latency(struct drm_crtc *crtc)
>  {
> -     struct drm_device *dev = crtc->dev;
> -     struct drm_i915_private *dev_priv = dev->dev_private;
> -     enum pipe pipe = to_intel_crtc(crtc)->pipe;
> -     int plane_prec, plane_dl;
> -     int cursor_prec, cursor_dl;
> -     int plane_prec_mult, cursor_prec_mult;
> -
> -     if (vlv_compute_drain_latency(dev, pipe, &plane_prec_mult, &plane_dl,
> -                                   &cursor_prec_mult, &cursor_dl)) {
> -             cursor_prec = (cursor_prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> -                     DDL_CURSOR_PRECISION_64 : DDL_CURSOR_PRECISION_32;
> -             plane_prec = (plane_prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> -                     DDL_PLANE_PRECISION_64 : DDL_PLANE_PRECISION_32;
> -
> -             I915_WRITE(VLV_DDL(pipe), cursor_prec |
> -                        (cursor_dl << DDL_CURSOR_SHIFT) |
> -                        plane_prec | (plane_dl << DDL_PLANE_SHIFT));
> +     struct drm_i915_private *dev_priv = crtc->dev->dev_private;
> +     struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +     int pixel_size;
> +     int drain_latency;
> +     enum pipe pipe = intel_crtc->pipe;
> +     int plane_prec, prec_mult, plane_dl;
> +
> +     plane_dl = I915_READ(VLV_DDL(pipe)) & ~(DDL_PLANE_PRECISION_64 |
> +                DRAIN_LATENCY_MASK | DDL_CURSOR_PRECISION_64 |
> +                (DRAIN_LATENCY_MASK << DDL_CURSOR_SHIFT));
> +
> +     if (!intel_crtc_active(crtc)) {
> +             I915_WRITE(VLV_DDL(pipe), plane_dl);
> +             return;
> +     }
> +
> +     /* Primary plane Drain Latency */
> +     pixel_size = crtc->primary->fb->bits_per_pixel / 8;     /* BPP */
> +     if (vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, 
> &drain_latency)) {
> +             plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> +                                        DDL_PLANE_PRECISION_64 :
> +                                        DDL_PLANE_PRECISION_32;
> +             plane_dl = plane_dl | plane_prec | drain_latency;

Could use the |= operator here. Using = and | makes my brain think
there's something more subtle going on when there isn't.

>       }
> +
> +     /* Cursor Drain Latency
> +      * BPP is always 4 for cursor
> +      */
> +     pixel_size = 4;
> +
> +     /* Program cursor DL only if it is enabled */
> +     if (intel_crtc->cursor_base &&
> +         vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, 
> &drain_latency)) {
> +             plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> +                                        DDL_CURSOR_PRECISION_64 :
> +                                        DDL_CURSOR_PRECISION_32;
> +             plane_dl = plane_dl | plane_prec |
> +                        drain_latency << DDL_CURSOR_SHIFT;

Same here.

Also doesn't gcc warn about adding parenthesis here with | and << ?
The code does the right thing here, but IIRC gcc likes to warn about
these. We like to keep the code reasonably free of compiler and
sparse warnings.

> +     }
> +
> +     I915_WRITE(VLV_DDL(pipe), plane_dl);
>  }
>  
>  #define single_plane_enabled(mask) is_power_of_2(mask)
> -- 
> 1.7.9.5
> 
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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