diff options
| author |   Ville Syrjälä <ville.syrjala@linux.intel.com> | 2019-10-02 19:25:05 +0300 |
|---|---|---|
| committer | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2019-10-31 16:08:11 +0200 |
| commit | 29b27657dbae8d4c4bdc6bfbf6dd8c69f648e075 (patch) | |
| tree | df73d25b22eeb63f496837f48426a08ddc422b33 /drivers/gpu/drm/i915/display/intel_dp_mst.c | |
| parent | drm/i915: Simplify pipe_mask setup even further (diff) | |
| download | linux-dev-29b27657dbae8d4c4bdc6bfbf6dd8c69f648e075.tar.xz linux-dev-29b27657dbae8d4c4bdc6bfbf6dd8c69f648e075.zip | |
drm/i915/mst: Document the userspace fail with possible_crtcs
To avoid accidentally breaking things in the future add a
comment explaining why we misconfigure the pipe_mask.
Also toss in a TODO for investigating a single encoder
approach as opposed to the encoder-per-pipe approach.
v2: Drop a bogus TODO comment
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191002162505.30716-6-ville.syrjala@linux.intel.com
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Diffstat (limited to '')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dp_mst.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 7370c9dfa8a1..715b7109c388 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -615,6 +615,14 @@ intel_dp_create_fake_mst_encoder(struct intel_digital_port *intel_dig_port, enum intel_encoder->power_domain = intel_dig_port->base.power_domain; intel_encoder->port = intel_dig_port->base.port; intel_encoder->cloneable = 0; + /* + * This is wrong, but broken userspace uses the intersection + * of possible_crtcs of all the encoders of a given connector + * to figure out which crtcs can drive said connector. What + * should be used instead is the union of possible_crtcs. + * To keep such userspace functioning we must misconfigure + * this to make sure the intersection is not empty :( + */ intel_encoder->pipe_mask = ~0; intel_encoder->compute_config = intel_dp_mst_compute_config; |