On 2019-10-17 12:28 a.m., Liu, Zhan wrote:
> From: Zhan Liu <zhan.liu@xxxxxxx>
>
> [Why]
> When a specific kind of connector is detected,
> DC needs to set the attribute of the stream.
> This step needs to be done before enabling link,
> or some bugs (e.g. display won't light up)
> will be observed.
>
> [How]
> Setting the attribute of the stream first, then
> enabling stream.
>
> Signed-off-by: Zhan Liu <zhan.liu@xxxxxxx>
NAK:
1. It's difficult to understand what issue this change is attempting to
solve and why it actually does it. Specifics would help here.
2. It affects a common code path for all ASICs which has been tested and
known to be working correctly for those test cases.
3. The description is incorrect - the link enable/stream enable were
both previously happening after the stream setup. What's changed in the
patch is the link enable now happens before the link setup.
Both of these calls internally go through the command table to VBIOS so
what behavior differences you're seeing may be caused by the input
parameters to the ATOM_ENCODER_CMD_STREAM_SETUP or
TRANSMITTER_CONTROL_ENABLE commands or the actual execution of those
commands.
Nicholas Kazlauskas
> ---
> drivers/gpu/drm/amd/display/dc/core/dc_link.c | 20 +++++++++----------
> 1 file changed, 10 insertions(+), 10 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 fb18681b502b..713caab82837 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
> @@ -2745,16 +2745,6 @@ void core_link_enable_stream(
> dc_is_virtual_signal(pipe_ctx->stream->signal))
> return;
>
> - if (!dc_is_virtual_signal(pipe_ctx->stream->signal)) {
> - stream->link->link_enc->funcs->setup(
> - stream->link->link_enc,
> - pipe_ctx->stream->signal);
> - pipe_ctx->stream_res.stream_enc->funcs->setup_stereo_sync(
> - pipe_ctx->stream_res.stream_enc,
> - pipe_ctx->stream_res.tg->inst,
> - stream->timing.timing_3d_format != TIMING_3D_FORMAT_NONE);
> - }
> -
> if (dc_is_dp_signal(pipe_ctx->stream->signal))
> pipe_ctx->stream_res.stream_enc->funcs->dp_set_stream_attribute(
> pipe_ctx->stream_res.stream_enc,
> @@ -2841,6 +2831,16 @@ void core_link_enable_stream(
> CONTROLLER_DP_TEST_PATTERN_VIDEOMODE,
> COLOR_DEPTH_UNDEFINED);
>
> + if (!dc_is_virtual_signal(pipe_ctx->stream->signal)) {
> + stream->link->link_enc->funcs->setup(
> + stream->link->link_enc,
> + pipe_ctx->stream->signal);
> + pipe_ctx->stream_res.stream_enc->funcs->setup_stereo_sync(
> + pipe_ctx->stream_res.stream_enc,
> + pipe_ctx->stream_res.tg->inst,
> + stream->timing.timing_3d_format != TIMING_3D_FORMAT_NONE);
> + }
> +
> #ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
> if (pipe_ctx->stream->timing.flags.DSC) {
> if (dc_is_dp_signal(pipe_ctx->stream->signal) ||
> --
> 2.17.1
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