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 DB01D4CE68A for ; Mon, 5 Oct 2026 20:15:42 +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=1791231344; cv=none; b=aCJ6LNZJbwv3jhujeNVrKqnmfHR997sZ2T+agyy7lwdFQFvOkx4tcQWr8+euT+nCgPiBv4oWx/SDtPJvcVieeb/ZTtXI5Njy0jS15QXl2noyZEDQdGM0Of+kdwXy6z9h1Yn3sZa+5E7OKHhCwdyKdSEOeFvdK8/YkbV0/pVQbvw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791231344; c=relaxed/simple; bh=QwxDB1FpYafbNsLTcJjfhQKWrqKqlDwEs+muxCcA3Sc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O7Bm9++mZjFG5npB/cGvpdffG9pmHnstJ0SJ+EtUXiyuIObHsdn7CdEFmXtCMQIh8OfGgNSaW5rzB6olhhrTS2QFDlTHa+iQPx5707t1/l2Lfx01y8KpDieD3l19BkUufVUxNcVI/oUzrdvlVsnJ/GTvmstyyJPUaUMx6q+pQE4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jP3j5NQS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jP3j5NQS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B98F41F00893; Mon, 5 Oct 2026 20:15:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791231342; bh=IByj082Dz4VkRreboErMETumX13OH5Qz2qksEygUklo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jP3j5NQSLpsr2vhoMt5hxCKK4fjRgLLZf7AOqy73rkqKxW+vmVZDtDc0z4yFik11U ofJld4rpyJwBDvMsWwSfc9XKqnWKyrc7VSZcdPCmLiwTUcYi1JZ9+8VzT0BWEoeXcv MZOR4LwJQkW2wyq0k41YSBSwsdccmA05dUnfRuz6yZbM7tisoRJkzXM9l58nt5fqF4 czBskEr5LVxf92zDWLePjmBj18NMsQjJ8WSRXa/J439jPgW78JND4BrYtHN3elXQlQ ZD5X4Fi1iEtA0T1mqs/kSa0rHdZmMRmkZSHawJysyoeDTmrDU1PcYMNw6r4vPrS+tj 79us5IOQURpdw== From: Sasha Levin To: stable@vger.kernel.org Cc: Arthur Heymans , George Zhang , Alex Hung , Dan Wheeler , Alex Deucher , Sasha Levin Subject: [PATCH 6.6.y] drm/amd/display: Preserve eDP mode on initial ASSR failure Date: Mon, 5 Oct 2026 16:15:37 -0400 Message-ID: <20261005201510.3061340-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026100542-ripening-rematch-74c5@gregkh> References: <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-Transfer-Encoding: 8bit From: Arthur Heymans [ Upstream commit 5e08102d1d336593160d1434261d50b0c0f6cbe6 ] 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 [ sashal: Applied the ASSR guard in perform_link_training_with_retries() instead of the absent edp_set_panel_assr() helper. ] Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/dc.h | 1 + .../gpu/drm/amd/display/dc/link/protocols/link_dp_training.c | 3 ++- .../drm/amd/display/dc/link/protocols/link_edp_panel_control.c | 1 + 3 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h index 88e64b280c90f..1f4292336692e 100644 --- a/drivers/gpu/drm/amd/display/dc/dc.h +++ b/drivers/gpu/drm/amd/display/dc/dc.h @@ -1512,6 +1512,7 @@ struct dc_link { 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_dp_training.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c index 539f57858dfec..aa46e0e84ce4f 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c @@ -1608,7 +1608,8 @@ bool perform_link_training_with_retries( */ bool result; 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; } } 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 d4d92da153ece..9f7ace40092ba 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 @@ -88,6 +88,7 @@ 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("Link: %d eDP panel mode supported: %d " "eDP panel mode enabled: %d \n", link->link_index, -- 2.53.0