From: Ville Syrjälä <ville.syrj...@linux.intel.com>
Populate conn_state->max_bpc with something sensible from the start.
Otherwise it's possible that we get to compute_sink_pipe_bpp() with
max_bpc==0.
The specific scenario goes as follows:
1. Initial connector state allocated with max_bpc==0
2. Trigger a modeset on the crtc feeding the connector, without
actually adding the connector to the commit
3. drm_atomic_connector_check() is skipped because the
connector has not yet been added, hence conn_state->max_bpc
retains its current value
4. drm_atomic_helper_check_modeset() ->
drm_atomic_add_affected_connectors() -> the connector
is now part of the commit
5. compute_baseline_pipe_bpp() -> MISSING_CASE(max_bpc==0)
Note that pipe_bpp itself may not be populated on pre-g4x machines,
in which case we just fall back to max_bpc==8 and let .compute_config()
limit the resulting pipe_bpp further if necessary.
Cc: Daniel Vetter <dan...@ffwll.ch>
Reported-by: Chris Wilson <ch...@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
drivers/gpu/drm/i915/display/intel_display.c | 24 +++++++++++++-------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c
b/drivers/gpu/drm/i915/display/intel_display.c
index 0dc5cb36667a..4d63e68a5ea2 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -7987,19 +7987,27 @@ static void
intel_modeset_update_connector_atomic_state(struct drm_device *dev)
drm_connector_list_iter_begin(dev, &conn_iter);
for_each_intel_connector_iter(connector, &conn_iter) {
- if (connector->base.state->crtc)
+ struct drm_connector_state *conn_state = connector->base.state;
+ struct intel_encoder *encoder =
+ to_intel_encoder(connector->base.encoder);
+
+ if (conn_state->crtc)
drm_connector_put(&connector->base);
- if (connector->base.encoder) {
- connector->base.state->best_encoder =
- connector->base.encoder;
- connector->base.state->crtc =
- connector->base.encoder->crtc;
+ if (encoder) {
+ struct intel_crtc *crtc =
+ to_intel_crtc(encoder->base.crtc);
+ const struct intel_crtc_state *crtc_state =
+ to_intel_crtc_state(crtc->base.state);
+
+ conn_state->best_encoder = &encoder->base;
+ conn_state->crtc = &crtc->base;
+ conn_state->max_bpc = (crtc_state->pipe_bpp ?: 24) / 3;
drm_connector_get(&connector->base);
} else {
- connector->base.state->best_encoder = NULL;
- connector->base.state->crtc = NULL;
+ conn_state->best_encoder = NULL;
+ conn_state->crtc = NULL;
}
}
drm_connector_list_iter_end(&conn_iter);
--
2.26.2
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