Re: [PATCH v3] drm/i915: Generalize drain latency computation

Ville Syrjälä
2014-08-06T15:09:09Z

On Thu, Aug 07, 2014 at 01:58:24AM +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
>
> v3: Changed to bitwise shorthand operator for plane_dl assignment.
>
> Signed-off-by: Gajanan Bhat <gajanan.bhat@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
> drivers/gpu/drm/i915/i915_reg.h | 1 +
> drivers/gpu/drm/i915/intel_pm.c | 87 ++++++++++++++++++++++-----------------
> 2 files changed, 51 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 187f862..08916df 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4009,6 +4009,7 @@ 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 ba8dfeb..cabea4b 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -1277,33 +1277,24 @@ 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;
> }
> @@ -1318,24 +1309,46 @@ 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_prec | drain_latency;
> }
> +
> + /* 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_prec | (drain_latency << DDL_CURSOR_SHIFT);
> + }
> +
> + 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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--
Ville Syrjälä
Intel OTC