Commit e838bfa8 authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

Revert "drm/i915: Fix DP-MST crtc_mask"

This reverts commit 4eaceea3.

Several userspace clients (modesetting ddx and mutter+wayland at least)
handle encoder.possible_crtcs incorrectly. What they essentially do is
the following:

possible_crtcs = ~0;
	possible_crtcs &= encoder->possible_crtcs;

Ie. they calculate the intersection of the possible_crtcs
for the connector when they really should be calculating the
union instead.

In our case each MST encoder now has just one unique bit set,
and so the intersection is always zero. The end result is that
MST connectors can't be lit up because no crtc can be found to
drive them.

I've submitted a fix for the modesetting ddx [1], and complained
on #wayland about mutter, so hopefully the situation will improve
in the future. In the meantime we have regression, and so must go
back to the old way of misconfiguring possible_crtcs in the kernel.


Cc: Jonas Ådahl <>
Cc: Stanislav Lisovskiy <>
Cc: Lionel Landwerlin <>
Cc: Dhinakaran Pandiyan <>
Cc: Lucas De Marchi <>

Signed-off-by: default avatarVille Syrjälä <>

Reviewed-by: default avatarJosé Roberto de Souza <>
parent 9d7b01e9
......@@ -615,7 +615,7 @@ intel_dp_create_fake_mst_encoder(struct intel_digital_port *intel_dig_port, enum
intel_encoder->type = INTEL_OUTPUT_DP_MST;
intel_encoder->power_domain = intel_dig_port->base.power_domain;
intel_encoder->port = intel_dig_port->base.port;
intel_encoder->crtc_mask = BIT(pipe);
intel_encoder->crtc_mask = 0x7;
intel_encoder->cloneable = 0;
intel_encoder->compute_config = intel_dp_mst_compute_config;
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