4fc1609bcd
[Why] Fixes issue when we have a display connected using a passive dongle and then emulate over it using a DP connection at 1 x 1.62 Ghz. System hangs because register bus returns back 0xFFFFFFFF for all register reads after setting register DIG_BE_CNTL in dcn10_link_encoder_connect_dig_be_to_fe(). Hang occurs later when trying to do a register read. [How] At the start of the emulation, dc_link_set_preferred_link_settings() and dp_retrain_link_dp_test() is called, even though it is connected using a passive dongle. Add an extra condition in dp_retrain_link_dp_test() to check for link->dongle_max_pix_clk > 0. This is the only way we know if the connection is using passive dongle so we don't retrain DP. Signed-off-by: Samson Tam <Samson.Tam@amd.com> Reviewed-by: Jun Lei <Jun.Lei@amd.com> Acked-by: Leo Li <sunpeng.li@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Linux kernel
============
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