From: Matt Roper matthew.d.roper@intel.com
When we write watermark values to the hardware, those values are stored in dev_priv->wm.skl_hw. However with recent watermark changes, the results structure we're copying from only contains valid watermark and DDB values for the pipes that are actually changing; the values for other pipes remain 0. Thus a blind copy of the entire skl_wm_values structure will clobber the values for unchanged pipes...we need to be more selective and only copy over the values for the changing pipes.
This mistake was hidden until recently due to another bug that caused us to erroneously re-calculate watermarks for all active pipes rather than changing pipes. Only when that bug was fixed was the impact of this bug discovered (e.g., modesets failing with "Requested display configuration exceeds system watermark limitations" messages and leaving watermarks non-functional, even ones initiated by intel_fbdev_restore_mode).
Changes since v1: - Add a function for copying a pipe's wm values (skl_copy_wm_for_pipe()) so we can reuse this later
Fixes: 734fa01f3a17 ("drm/i915/gen9: Calculate watermarks during atomic 'check' (v2)") Fixes: 9b6130227495 ("drm/i915/gen9: Re-allocate DDB only for changed pipes") Signed-off-by: Matt Roper matthew.d.roper@intel.com Signed-off-by: Lyude cpaul@redhat.com Reviewed-by: Matt Roper matthew.d.roper@intel.com Cc: stable@vger.kernel.org Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Daniel Vetter daniel.vetter@intel.com Cc: Radhakrishna Sripada radhakrishna.sripada@intel.com Cc: Hans de Goede hdegoede@redhat.com --- drivers/gpu/drm/i915/intel_pm.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 68721a5..7fd299e 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -4064,6 +4064,24 @@ skl_compute_ddb(struct drm_atomic_state *state) return 0; }
+static void +skl_copy_wm_for_pipe(struct skl_wm_values *dst, + struct skl_wm_values *src, + enum pipe pipe) +{ + dst->wm_linetime[pipe] = src->wm_linetime[pipe]; + memcpy(dst->plane[pipe], src->plane[pipe], + sizeof(dst->plane[pipe])); + memcpy(dst->plane_trans[pipe], src->plane_trans[pipe], + sizeof(dst->plane_trans[pipe])); + + dst->ddb.pipe[pipe] = src->ddb.pipe[pipe]; + memcpy(dst->ddb.y_plane[pipe], src->ddb.y_plane[pipe], + sizeof(dst->ddb.y_plane[pipe])); + memcpy(dst->ddb.plane[pipe], src->ddb.plane[pipe], + sizeof(dst->ddb.plane[pipe])); +} + static int skl_compute_wm(struct drm_atomic_state *state) { @@ -4136,8 +4154,10 @@ static void skl_update_wm(struct drm_crtc *crtc) struct drm_device *dev = crtc->dev; struct drm_i915_private *dev_priv = to_i915(dev); struct skl_wm_values *results = &dev_priv->wm.skl_results; + struct skl_wm_values *hw_vals = &dev_priv->wm.skl_hw; struct intel_crtc_state *cstate = to_intel_crtc_state(crtc->state); struct skl_pipe_wm *pipe_wm = &cstate->wm.skl.optimal; + int pipe;
if ((results->dirty_pipes & drm_crtc_mask(crtc)) == 0) return; @@ -4149,8 +4169,12 @@ static void skl_update_wm(struct drm_crtc *crtc) skl_write_wm_values(dev_priv, results); skl_flush_wm_values(dev_priv, results);
- /* store the new configuration */ - dev_priv->wm.skl_hw = *results; + /* + * Store the new configuration (but only for the pipes that have + * changed; the other values weren't recomputed). + */ + for_each_pipe_masked(dev_priv, pipe, results->dirty_pipes) + skl_copy_wm_for_pipe(hw_vals, results, pipe);
mutex_unlock(&dev_priv->wm.wm_mutex); }