From c2192872d99b8bc7d1ac2494e850fb6fb6c915eb Mon Sep 17 00:00:00 2001 From: =?utf8?q?Timur=20Krist=C3=B3f?= Date: Fri, 26 Sep 2025 20:01:49 +0200 Subject: [PATCH] drm/amd/display: Determine early if a link has supported encoders (v2) MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Avoid initializing DDC, HPD, etc. when we know that the link is not going to be constructed because it has no supported encoders. This is mainly useful for old GPUs which may have encoders such as TRAVIS and NUTMEG that are not yet supported by DC. Signed-off-by: Timur Kristóf Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher --- .../drm/amd/display/dc/link/link_factory.c | 23 +++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/link/link_factory.c b/drivers/gpu/drm/amd/display/dc/link/link_factory.c index f06af98d46ee8..8899797f64a9c 100644 --- a/drivers/gpu/drm/amd/display/dc/link/link_factory.c +++ b/drivers/gpu/drm/amd/display/dc/link/link_factory.c @@ -451,6 +451,14 @@ static enum channel_id get_ddc_line(struct dc_link *link) return channel; } +static bool transmitter_supported(const enum transmitter transmitter) +{ + return transmitter != TRANSMITTER_UNKNOWN && + transmitter != TRANSMITTER_NUTMEG_CRT && + transmitter != TRANSMITTER_TRAVIS_CRT && + transmitter != TRANSMITTER_TRAVIS_LCD; +} + static bool construct_phy(struct dc_link *link, const struct link_init_data *init_params) { @@ -482,6 +490,17 @@ static bool construct_phy(struct dc_link *link, link->link_id = bios->funcs->get_connector_id(bios, init_params->connector_index); + /* Determine early if the link has any supported encoders, + * so that we avoid initializing DDC and HPD, etc. + */ + bp_funcs->get_src_obj(bios, link->link_id, 0, &enc_init_data.encoder); + enc_init_data.transmitter = translate_encoder_to_transmitter(enc_init_data.encoder); + + if (!transmitter_supported(enc_init_data.transmitter)) { + DC_LOG_WARNING("link_id %d has unsupported encoder\n", link->link_id.id); + return false; + } + link->ep_type = DISPLAY_ENDPOINT_PHY; DC_LOG_DC("BIOS object table - link_id: %d", link->link_id.id); @@ -611,16 +630,12 @@ static bool construct_phy(struct dc_link *link, dal_ddc_get_line(get_ddc_pin(link->ddc)); enc_init_data.ctx = dc_ctx; - bp_funcs->get_src_obj(dc_ctx->dc_bios, link->link_id, 0, - &enc_init_data.encoder); enc_init_data.connector = link->link_id; enc_init_data.channel = get_ddc_line(link); enc_init_data.hpd_source = get_hpd_line(link); link->hpd_src = enc_init_data.hpd_source; - enc_init_data.transmitter = - translate_encoder_to_transmitter(enc_init_data.encoder); link->link_enc = link->dc->res_pool->funcs->link_enc_create(dc_ctx, &enc_init_data); -- 2.47.3