On Wed, May 17, 2017 at 05:28:29PM +0530, Mahesh Kumar wrote:
> From: "Kumar, Mahesh" <mahesh1.kumar@xxxxxxxxx>
>
> This patch make changes to use linetime latency if allocated
> DDB size during plane watermark calculation is not available.
> linetime is the time, display engine takes to fetch one line worth of
> pixels with given pixel clock rate.
> This is required to implement new DDB allocation algorithm.
>
> In New Algorithm DDB is allocated based on WM values, because of which
> number of DDB blocks will not be available during WM calculation,
> So this "linetime latency" is suggested by SV/HW team to be used during
> switch-case for WM blocks selection.
> linetime latency us = pipe horizontal total pixels/adjusted pixel rate MHz
>
> Changes since v1:
> - Rebase on top of Paulo's patch series
> Changes since v2:
> - Fix if-else condition (pointed by Maarten)
> Changes since v3:
> - Use common function for timetime_us calculation (Paulo)
> - rebase on drm-tip
> Changes since v4:
> - Use consistent name for fixed_point operation
> Changes since v5:
> - Improve commit message
> - rename skl_get_linetime_us to intel_get_linetime_us
> - fix watermark result selection (Matt)
>
> Signed-off-by: "Mahesh Kumar" <mahesh1.kumar@xxxxxxxxx>
> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 7 +++++++
> drivers/gpu/drm/i915/intel_pm.c | 42 ++++++++++++++++++++++++++++++++---------
> 2 files changed, 40 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index e9144634e720..0100100fdaf9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -115,6 +115,13 @@ typedef struct {
> fp; \
> })
>
> +static inline bool is_fixed16_zero(uint_fixed_16_16_t val)
> +{
> + if (val.val == 0)
> + return true;
> + return false;
> +}
> +
> static inline uint_fixed_16_16_t u32_to_fixed_16_16(uint32_t val)
> {
> uint_fixed_16_16_t fp;
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 0f1d9f672e83..936eef1634c7 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4197,6 +4197,27 @@ static uint_fixed_16_16_t skl_wm_method2(uint32_t pixel_rate,
> return ret;
> }
>
> +static uint_fixed_16_16_t
> +intel_get_linetime_us(struct intel_crtc_state *cstate)
> +{
> + uint32_t pixel_rate;
> + uint32_t crtc_htotal;
> + uint_fixed_16_16_t linetime_us;
> +
> + if (!cstate->base.active)
> + return u32_to_fixed_16_16(0);
> +
> + pixel_rate = cstate->pixel_rate;
> +
> + if (WARN_ON(pixel_rate == 0))
> + return u32_to_fixed_16_16(0);
> +
> + crtc_htotal = cstate->base.adjusted_mode.crtc_htotal;
> + linetime_us = fixed_16_16_div_u64(crtc_htotal * 1000, pixel_rate);
> +
> + return linetime_us;
> +}
> +
> static uint32_t
> skl_adjusted_plane_pixel_rate(const struct intel_crtc_state *cstate,
> const struct intel_plane_state *pstate)
> @@ -4331,12 +4352,18 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
> if (y_tiled) {
> selected_result = max_fixed_16_16(method2, y_tile_minimum);
> } else {
> + uint32_t linetime_us;
> +
> + linetime_us = fixed_16_16_to_u32_round_up(
> + intel_get_linetime_us(cstate));
> if ((cpp * cstate->base.adjusted_mode.crtc_htotal / 512 < 1) &&
> (plane_bytes_per_line / 512 < 1))
> selected_result = method2;
> - else if ((ddb_allocation /
> + else if ((ddb_allocation && ddb_allocation /
> fixed_16_16_to_u32_round_up(plane_blocks_per_line)) >= 1)
> selected_result = min_fixed_16_16(method1, method2);
> + else if (latency >= linetime_us)
> + selected_result = min_fixed_16_16(method1, method2);
> else
> selected_result = method1;
> }
> @@ -4424,19 +4451,16 @@ skl_compute_linetime_wm(struct intel_crtc_state *cstate)
> {
> struct drm_atomic_state *state = cstate->base.state;
> struct drm_i915_private *dev_priv = to_i915(state->dev);
> - uint32_t pixel_rate;
> + uint_fixed_16_16_t linetime_us;
> uint32_t linetime_wm;
>
> - if (!cstate->base.active)
> - return 0;
> + linetime_us = intel_get_linetime_us(cstate);
>
> - pixel_rate = cstate->pixel_rate;
> -
> - if (WARN_ON(pixel_rate == 0))
> + if (is_fixed16_zero(linetime_us))
> return 0;
>
> - linetime_wm = DIV_ROUND_UP(8 * cstate->base.adjusted_mode.crtc_htotal *
> - 1000, pixel_rate);
> + linetime_wm = fixed_16_16_to_u32_round_up(mul_u32_fixed_16_16(8,
> + linetime_us));
>
> /* Display WA #1135: bxt. */
> if (IS_BROXTON(dev_priv) && dev_priv->ipc_enabled)
> --
> 2.11.0
>
--
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795
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