[PATCH 5.4 060/434] drm/amd/display: Handle virtual signal type in disable_link()

Greg Kroah-Hartman
2019-12-29T17:44:07Z

From: Martin Tsai <martin.tsai@amd.com>

[ Upstream commit 616f5b65f1c02d3d6ae370644670d14c57de2fd8 ]

[Why]
The new implementation changed the behavior to allow process setMode
to DAL when DAL returns empty mode query for unplugged display.
This will trigger additional disable_link().
When unplug HDMI from MST dock, driver will update stream->signal to
"Virtual". disable_link() will call disable_output() if the signal type
is not DP and induce other displays on MST dock show black screen.

[How]
Don't need to process disable_output() if the signal type is virtual.

Signed-off-by: Martin Tsai <martin.tsai@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/core/dc_link.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index ca20b150afcc..de1b61595ffb 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -2169,8 +2169,10 @@ static void disable_link(struct dc_link *link, enum signal_type signal)
dp_set_fec_ready(link, false);
}
#endif
- } else
- link->link_enc->funcs->disable_output(link->link_enc, signal);
+ } else {
+ if (signal != SIGNAL_TYPE_VIRTUAL)
+ link->link_enc->funcs->disable_output(link->link_enc, signal);
+ }

if (signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
/* MST disable link only when no stream use the link */
--
2.20.1