From: Samson Tam Samson.Tam@amd.com
[ Upstream commit 233d87a579b8adcc6da5823fa507ecb6675e7562 ]
[Why] Found issue in EDID Emulation where if we connect a display using a passive HDMI-DP dongle, disconnect it and then try to emulate a display using DP, we could not see 4K modes. This was because on a disconnect, dongle_max_pix_clk was still set so when we emulate using DP, in dc_link_validate_mode_timing(), it would think we were still using a dongle and limit the modes we support.
[How] In dc_link_detect(), set dongle_max_pix_clk to 0 when we detect a hotplug out ( if new_connection_type = dc_connection_none ).
Signed-off-by: Samson Tam Samson.Tam@amd.com Reviewed-by: Jun Lei Jun.Lei@amd.com Acked-by: Bhawanpreet Lakha Bhawanpreet.Lakha@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, 6 insertions(+)
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 b37ecc3ede61..a3ff33ff6da1 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -960,6 +960,12 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
link->type = dc_connection_none; sink_caps.signal = SIGNAL_TYPE_NONE; + /* When we unplug a passive DP-HDMI dongle connection, dongle_max_pix_clk + * is not cleared. If we emulate a DP signal on this connection, it thinks + * the dongle is still there and limits the number of modes we can emulate. + * Clear dongle_max_pix_clk on disconnect to fix this + */ + link->dongle_max_pix_clk = 0; }
LINK_INFO("link=%d, dc_sink_in=%p is now %s prev_sink=%p dpcd same=%d edid same=%d\n",