drm/i915/display: Disable SAGV on bw init, to force QGV point recalculation

Problem is that on some platforms, we do get QGV point mask in wrong
state on boot. However driver assumes it is set to 0
(i.e all points allowed), however in reality we might get them all
restricted, causing issues.
Lets disable SAGV initially to force proper QGV point state.
If more QGV points are available, driver will recalculate and update
those then after next commit.

v2: - Added trace to see which QGV/PSF GV point is used when SAGV is
      disabled.
v3: - Move force disable function to intel_bw_init in order to initialize
      bw state as well, so that hw/sw are immediately in sync after init.
v4: - Don't try sending PCode request, seems like it is not possible at
      intel_bw_init, however assigning bw->state to be restricted as if
      SAGV is off, still forces driveer to send PCode request anyway on
      next modeset, so the solution still works.
      However we still need to address the case, when no display is
      connected, which anyway requires much more changes.

v5: - Put PCode request back and apply temporary hack to make the
      request succeed(in case if there 2 PSF GV points with same BW, PCode
      accepts only if both points are restricted/unrestricted same time)
    - Fix argument sequence for adl_qgv_bw(Ville Syrjälä)

v6: - Fix wrong platform checks, not to break everything else.

v7: - Split the handling of quplicate QGV/PSF GV points (Vinod)
      Restrict force disable to display version below 14 (Vinod)

v8: - Simplify icl_force_disable_sagv (Vinod)

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240405113533.338553-5-vinod.govindapillai@intel.com

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/skl_watermark.h b/drivers/gpu/drm/i915/display/skl_watermark.h
index ef1a008466be..91f92c0e706e 100644
--- a/drivers/gpu/drm/i915/display/skl_watermark.h
+++ b/drivers/gpu/drm/i915/display/skl_watermark.h
@@ -25,6 +25,7 @@ void intel_sagv_pre_plane_update(struct intel_atomic_state *state);
 void intel_sagv_post_plane_update(struct intel_atomic_state *state);
 bool intel_can_enable_sagv(struct drm_i915_private *i915,
 			   const struct intel_bw_state *bw_state);
+bool intel_has_sagv(struct drm_i915_private *i915);
 
 u32 skl_ddb_dbuf_slice_mask(struct drm_i915_private *i915,
 			    const struct skl_ddb_entry *entry);