The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 5a9a2cc8ae1889c4002850b00fd4fd9691dfac4e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2024012753-radiation-single-4e58@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: 5a9a2cc8ae18 ("drm/amd/display: force toggle rate wa for first link training for a retimer") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5a9a2cc8ae1889c4002850b00fd4fd9691dfac4e Mon Sep 17 00:00:00 2001 From: Zhongwei <zhongwei.zhang@xxxxxxx> Date: Wed, 8 Nov 2023 16:34:36 +0800 Subject: [PATCH] drm/amd/display: force toggle rate wa for first link training for a retimer [WHY] Handover from DMUB to driver does not perform link rate toggle. It might cause link training failure for boot up. [HOW] Force toggle rate wa for first link train. link->vendor_specific_lttpr_link_rate_wa should be zero then. Cc: stable@xxxxxxxxxxxxxxx # 6.1+ Reviewed-by: Michael Strauss <michael.strauss@xxxxxxx> Acked-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx> Signed-off-by: Zhongwei <zhongwei.zhang@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c index fd8f6f198146..68096d12f52f 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c @@ -115,7 +115,7 @@ static enum link_training_result perform_fixed_vs_pe_nontransparent_training_seq lt_settings->cr_pattern_time = 16000; /* Fixed VS/PE specific: Toggle link rate */ - apply_toggle_rate_wa = (link->vendor_specific_lttpr_link_rate_wa == target_rate); + apply_toggle_rate_wa = ((link->vendor_specific_lttpr_link_rate_wa == target_rate) || (link->vendor_specific_lttpr_link_rate_wa == 0)); target_rate = get_dpcd_link_rate(<_settings->link_settings); toggle_rate = (target_rate == 0x6) ? 0xA : 0x6; @@ -271,7 +271,7 @@ enum link_training_result dp_perform_fixed_vs_pe_training_sequence_legacy( /* Vendor specific: Toggle link rate */ toggle_rate = (rate == 0x6) ? 0xA : 0x6; - if (link->vendor_specific_lttpr_link_rate_wa == rate) { + if (link->vendor_specific_lttpr_link_rate_wa == rate || link->vendor_specific_lttpr_link_rate_wa == 0) { core_link_write_dpcd( link, DP_LINK_BW_SET, @@ -617,7 +617,7 @@ enum link_training_result dp_perform_fixed_vs_pe_training_sequence( /* Vendor specific: Toggle link rate */ toggle_rate = (rate == 0x6) ? 0xA : 0x6; - if (link->vendor_specific_lttpr_link_rate_wa == rate) { + if (link->vendor_specific_lttpr_link_rate_wa == rate || link->vendor_specific_lttpr_link_rate_wa == 0) { core_link_write_dpcd( link, DP_LINK_BW_SET,
