From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B2E5377A98 for ; Mon, 5 Oct 2026 08:05:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791187557; cv=none; b=dhQuex+CmepQn6v0zqmiueFDGHxDMdNcsCKWBkRbpDpKZ5ZRorkgCRhLsbRTlg+mUZsRGQorPkV6fC6fETW7Xs503WZ4nYcN6wv+Wa3Ve5IoVeuZOo9g9NuBjrKWt0xjA+JPZRTA6wCq0K+hqh5/gOTnnryxtbACa8+lnniIbWE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791187557; c=relaxed/simple; bh=+SDBhrikZgLb9OpXDHUr5+PQ9fasKTsdLGOucn5p5Dw=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=tvRI5dRb7S1tBj7FvqA93FefV1ucnk+W9awl8vrij7b9ngBUENbC68QrubRb8WyFgr71sL1nOs7FsX//SrrPYRlI3Z/7XbhehGyTrWuABli8TX3ofF+bU09OB4OPUw110J3Dp5rN1dwowTUoaOfVY6hlQ+NH8h2sE/UtG4Wjg1E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AfFICirW; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AfFICirW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3368F1F000FF; Mon, 5 Oct 2026 08:05:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791187555; bh=3ZlbIvADeGua6G0kTfxo9fKqkah8Ls/EzuoPxvw+KW8=; h=Subject:To:Cc:From:Date; b=AfFICirWjOBSixjX1+sQ+gE+QLwUq26Xhjdino2fNHMxP8S5xZKQWiHnLdsL05JUW P4sHkPld6zUeJ37JBlQ36yU30JQ3RY7EBtDKbSkgzaaTONyDzp+YQ5UV5L4bdRCts2 LNsgIPgmT6N99ZLWyeQ9OKqFBO4C1xHkHFwFRNuc= Subject: FAILED: patch "[PATCH] drm/amd/display: Preserve eDP mode on initial ASSR failure" failed to apply to 6.6-stable tree To: arthur@aheymans.xyz,alex.hung@amd.com,alexander.deucher@amd.com,daniel.wheeler@amd.com,george.zhang@amd.com Cc: From: Date: Mon, 05 Oct 2026 10:05:42 +0200 Message-ID: <2026100542-ripening-rematch-74c5@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit 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 . 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 5e08102d1d336593160d1434261d50b0c0f6cbe6 # git commit -s git send-email --to '' --in-reply-to '2026100542-ripening-rematch-74c5@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5e08102d1d336593160d1434261d50b0c0f6cbe6 Mon Sep 17 00:00:00 2001 From: Arthur Heymans Date: Sat, 12 Sep 2026 17:11:37 +0200 Subject: [PATCH] drm/amd/display: Preserve eDP mode on initial ASSR failure Commit 56d8ce9d8c17 ("drm/amd/display: Apply correct panel mode when reinitializing hardware") made ASSR failure fall back to the default panel mode unless eDP mode had previously been applied. However, dc_link is zero-initialized and DP_PANEL_MODE_DEFAULT is zero. Before the first call to dp_set_panel_mode(), panel_mode therefore looks like a previously applied default mode. If ASSR setup fails during the first link training attempt, the driver incorrectly trains the eDP link using the default scrambling mode. On a Google Vilboz Chromebook running self-built coreboot firmware and PSP verstage, this leaves the panel mostly black with corrupted output along the top edge. Track whether panel_mode has actually been initialized, and only consult the saved mode after it has been applied. This retains the recovery behavior while preserving eDP mode during initial link training. Fixes: 56d8ce9d8c17 ("drm/amd/display: Apply correct panel mode when reinitializing hardware") Assisted-by: Pi:gpt-5.6-sol Reviewed-by: George Zhang Reviewed-by: Alex Hung Signed-off-by: Arthur Heymans Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit ccb6c2702033f1002b45807fb3cc938760f26f78) Cc: stable@vger.kernel.org # 6.4.x diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h index 705c500ad711..871063f809dc 100644 --- a/drivers/gpu/drm/amd/display/dc/dc.h +++ b/drivers/gpu/drm/amd/display/dc/dc.h @@ -1905,6 +1905,7 @@ struct dc_scratch_space { struct ddc_service *ddc; enum dp_panel_mode panel_mode; + bool panel_mode_initialized; bool aux_mode; /* Private to DC core */ diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c index 16951a9550f2..21dd91fc8010 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c @@ -93,6 +93,7 @@ void dp_set_panel_mode(struct dc_link *link, enum dp_panel_mode panel_mode) } link->panel_mode = panel_mode; + link->panel_mode_initialized = true; DC_LOG_DETECTION_DP_CAPS("%d eDP panel mode supported: %d, enabled: %d\n", link->link_index, link->dpcd_caps.panel_mode_edp, @@ -1297,7 +1298,8 @@ void edp_set_panel_assr(struct dc_link *link, struct pipe_ctx *pipe_ctx, result = cp_psp->funcs.enable_assr(cp_psp->handle, link); - if (!result && link->panel_mode != DP_PANEL_MODE_EDP) + if (!result && link->panel_mode_initialized && + link->panel_mode != DP_PANEL_MODE_EDP) *panel_mode = DP_PANEL_MODE_DEFAULT; } }