Re: [PATCH] drm/i915/skl: Don't clear all watermarks when updating. (v2)

[Damien Lespiau <damien.lespiau@intel.com>]

On Tue, Jul 21, 2015 at 10:42:53AM -0700, Bob Paauwe wrote:
> Clearing the watermarks for all pipes/planes when updating the
> watermarks for a single CRTC change seems like the wrong thing to
> do here. As is, this code will ony update any pipe/plane watermarks
> that need updating and leave the remaining set to zero.  Later, the
> watermark checks in check_wm_state() will flag these zero'd out pipe/plane
> watermarks and throw errors.
> 
> By clearing only the watermark values associated with the specific crtc
> the other watermark values may remain unchanged.
> 
> v2: Make sure all the dirty flags are cleared. Damien
>     Clear all values assoicated with crtc/pipe being updated.  Damien
> 
> Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>

Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>

- Moving to a "array of structs" from a "struct of arrays" organization
  as suggested by Ville would make that much better
- I'd move clearing the dirty flag right after writing the registers

-- 
Damien

> ---
>  drivers/gpu/drm/i915/intel_pm.c | 26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index a1d92b7..27c3126 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3670,6 +3670,26 @@ static void skl_update_other_pipe_wm(struct drm_device *dev,
>  	}
>  }
>  
> +static void skl_clear_wm(struct skl_wm_values *watermarks, enum pipe pipe)
> +{
> +	watermarks->wm_linetime[pipe] = 0;
> +	memset(watermarks->plane[pipe], 0,
> +	       sizeof(uint32_t) * 8 * I915_MAX_PLANES);
> +	memset(watermarks->cursor[pipe], 0, sizeof(uint32_t) * 8);
> +	memset(watermarks->plane_trans[pipe],
> +	       0, sizeof(uint32_t) * I915_MAX_PLANES);
> +	watermarks->cursor_trans[pipe] = 0;
> +
> +	/* Clear ddb entries for pipe */
> +	memset(&watermarks->ddb.pipe[pipe], 0, sizeof(struct skl_ddb_entry));
> +	memset(&watermarks->ddb.plane[pipe], 0,
> +	       sizeof(struct skl_ddb_entry) * I915_MAX_PLANES);
> +	memset(&watermarks->ddb.y_plane[pipe], 0,
> +	       sizeof(struct skl_ddb_entry) * I915_MAX_PLANES);
> +	memset(&watermarks->ddb.cursor[pipe], 0, sizeof(struct skl_ddb_entry));
> +
> +}
> +
>  static void skl_update_wm(struct drm_crtc *crtc)
>  {
>  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> @@ -3680,7 +3700,11 @@ static void skl_update_wm(struct drm_crtc *crtc)
>  	struct skl_pipe_wm pipe_wm = {};
>  	struct intel_wm_config config = {};
>  
> -	memset(results, 0, sizeof(*results));
> +
> +	/* Clear all dirty flags */
> +	memset(results->dirty, 0, sizeof(bool) * I915_MAX_PIPES);
> +
> +	skl_clear_wm(results, intel_crtc->pipe);
>  
>  	skl_compute_wm_global_parameters(dev, &config);
>  
> -- 
> 2.1.0
> 
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