Re: [PATCH v3 3/5] drm/i915/scaler: Compute scaling factors for pipe scaler

[Nautiyal, Ankit K]

On 1/6/2025 10:21 PM, Mitul Golani wrote:
Compute scaling factors and scaler user for pipe scaler if
particular scaler user is pipe scaler.

--v2:
- Update typo 'plane scaling' to 'pipe scaling'. [Ankit]
- Remove FIXME tag which was added to check for pipe scaling
factors as well. [Ankit]
- Should be common hscale, vscale instead of local one to
avoid garbage overwritten.
- Typo in commit message 'perticular' to 'particular'.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.gol...@intel.com>
---
  drivers/gpu/drm/i915/display/skl_scaler.c | 34 ++++++++++++++++++-----
  1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/skl_scaler.c 
b/drivers/gpu/drm/i915/display/skl_scaler.c
index 4f838220f880..294493e5ee53 100644
--- a/drivers/gpu/drm/i915/display/skl_scaler.c
+++ b/drivers/gpu/drm/i915/display/skl_scaler.c
@@ -320,6 +320,7 @@ static int intel_atomic_setup_scaler(struct 
intel_crtc_state *crtc_state,
                                        &crtc_state->scaler_state;
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        u32 mode;
+       int hscale, vscale;
  
  	if (*scaler_id < 0)
                *scaler_id = intel_allocate_scaler(scaler_state, crtc);
@@ -368,15 +369,11 @@ static int intel_atomic_setup_scaler(struct 
intel_crtc_state *crtc_state,
                mode = SKL_PS_SCALER_MODE_DYN;
        }
  
-	/*
-        * FIXME: we should also check the scaler factors for pfit, so
-        * this shouldn't be tied directly to planes.
-        */
        if (plane_state && plane_state->hw.fb) {
                const struct drm_framebuffer *fb = plane_state->hw.fb;
                const struct drm_rect *src = &plane_state->uapi.src;
                const struct drm_rect *dst = &plane_state->uapi.dst;
-               int hscale, vscale, max_vscale, max_hscale;
+               int max_vscale, max_hscale;
  
  		/*
                 * FIXME: When two scalers are needed, but only one of
@@ -426,11 +423,34 @@ static int intel_atomic_setup_scaler(struct 
intel_crtc_state *crtc_state,
  
  			return -EINVAL;
                }
+       }
+
+       if (crtc_state->pch_pfit.enabled) {
+               struct drm_rect src;
+
+               drm_rect_init(&src, 0, 0,
+                             drm_rect_width(&crtc_state->pipe_src) << 16,
+                             drm_rect_height(&crtc_state->pipe_src) << 16);
+
+               hscale = drm_rect_calc_hscale(&src, &crtc_state->pch_pfit.dst,
+                                             0, INT_MAX);
+               vscale = drm_rect_calc_vscale(&src, &crtc_state->pch_pfit.dst,
+                                             0, INT_MAX);

We need to do similar to plane scaler case, to check if hscale/vscale 
are less than the max scaling values.

I think it would be better to make a function to get max_hscale and 
vscale for a platform.

With 420 encoding, there is different limit so need to account that too. 
e.g Bspec:50441


Regards,

Ankit



  
-		scaler_state->scalers[*scaler_id].hscale = hscale;
-               scaler_state->scalers[*scaler_id].vscale = vscale;
+               if (hscale < 0 || vscale < 0) {
+                       drm_dbg_kms(display->drm,
+                                   "Scaler %d doesn't support required pipe 
scaling\n",
+                                   *scaler_id);
+                       drm_rect_debug_print("src: ", &src, true);
+                       drm_rect_debug_print("dst: ", 
&crtc_state->pch_pfit.dst, false);
+
+                       return -EINVAL;
+               }
        }
  
+	scaler_state->scalers[*scaler_id].hscale = hscale;
+       scaler_state->scalers[*scaler_id].vscale = vscale;
+
        drm_dbg_kms(display->drm, "Attached scaler id %u.%u to %s:%d\n",
                    crtc->pipe, *scaler_id, name, idx);
        scaler_state->scalers[*scaler_id].mode = mode;