From 813ab774abc9aaf63b802607948ec1fe7cf5e7af Mon Sep 17 00:00:00 2001 From: JinZe Xu <jinze.xu@amd.com> Date: Tue, 20 Jun 2023 08:31:00 -0700 Subject: [PATCH] drm/amd/display: Setup stream encoder before link enable for TMDS [Why] HDMI spec requires TMDS clock to be not more than 340MHz. Stream encoder ensure this requirement but driver enable stream encoder later than PHY. So PHY will output full speed TMDS clock first. [How] Enable stream encoder first in TMDS case. Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> Acked-by: Alan Liu <haoping.liu@amd.com> Signed-off-by: JinZe Xu <jinze.xu@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> --- drivers/gpu/drm/amd/display/dc/link/link_dpms.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c index 1a7b93e41e352..d8fcff0e5319b 100644 --- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c +++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c @@ -1971,6 +1971,7 @@ static void enable_link_hdmi(struct pipe_ctx *pipe_ctx) bool is_vga_mode = (stream->timing.h_addressable == 640) && (stream->timing.v_addressable == 480); struct dc *dc = pipe_ctx->stream->ctx->dc; + const struct link_hwss *link_hwss = get_link_hwss(link, &pipe_ctx->link_res); if (stream->phy_pix_clk == 0) stream->phy_pix_clk = stream->timing.pix_clk_100hz / 10; @@ -2010,6 +2011,12 @@ static void enable_link_hdmi(struct pipe_ctx *pipe_ctx) if (stream->timing.pixel_encoding == PIXEL_ENCODING_YCBCR422) display_color_depth = COLOR_DEPTH_888; + /* We need to enable stream encoder for TMDS first to apply 1/4 TMDS + * character clock in case that beyond 340MHz. + */ + if (dc_is_hdmi_tmds_signal(pipe_ctx->stream->signal)) + link_hwss->setup_stream_encoder(pipe_ctx); + dc->hwss.enable_tmds_link_output( link, &pipe_ctx->link_res, -- GitLab