From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794049139; b=DwvHTZtmb23u6aC3Um/nXhvnfyDi7HekF/05ehFeW0qgnvdnMX3HcpiYte6vQgjnRJfe rblUXwnJ9ID8PisGtdkxBvrisAMRZMIFLSMLqozdWfI9UZl92c71xP/i2azw/Rt7KEwwQ wIi1VkSOJjjk7/lZuNL7bbXPOl51FoVuz85puKHWuKgzl3SAC46+8FXLFRQUHM69EVaxS dkZ7OtA21ZbCchHQkWDAVMIg4pD7kgdjzAJttBOh0TypWqpzMOzGaPHmLlV+lteHDMX8Z dQDlGSl76OAeMPUnMSvCfavahsW3uUHZEOsxrBUC4AnCIW4HrKZG4fGlnpI/2d6EoNA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794049139; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=kaSNmKf6u8V5iKkSiqRT75BhOCqwUHnF4kLOFQYdekE=; b=yWKElgJnAeLAxagyN0JpUplH3AQk+rbiMdaROIpbHcusdBufzBS0E3BNhi1DgWpIYah/ jseNzVvhZp9VafhurgnsUkxuF95Se9oRPCfURVQiGuCvJ2htb96q8Rc8sigtsvxLJFfTy JblzuDjt9YLzR6qkQ62Ln8vbWO6D2MKFMwkw9BnhkZz9SGMmdVsRiWfwl0pFnNqeMbB+D ZJKzcsBthdYH9QWS4AQPgQ+FtF8Eq7xsF0b9tdn/Cuk5SQvzm7LTlYbMKGN+PiUh0Z585 oEQF22CaP65pp9DA1XE9wmb1UQAkQg4O4Lk+6zkppTP52nce/SSgw1Pu38/pT560MYQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Ff9+YulL; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 57626606A32E for ; Sat, 7 Nov 2026 10:58:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Ff9+YulL Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90E111F0089F; Sat, 7 Nov 2026 10:58:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794049139; bh=kaSNmKf6u8V5iKkSiqRT75BhOCqwUHnF4kLOFQYdekE=; h=From:To:Cc:Subject:Date; b=Ff9+YulLBj3DJD13+VFYNYgQo3ueJ8Is1hVwolT662RoI7uZSCnZU1GBpgPl9UiOi QedLpAZ8bRjUtIlrKd8dGulrezGQai5YV/0bUa1RGiZKL7Dez6jloqKIrgy+ayA6M4 +EFMFd2G7mdSYzzaSsJ9B7He0qKK8ZtfRPvzFd/h4ZqkN7Z599bQof5fLxL20x+Ogz ZK7DjBb7nbAH0uy0OGFQY1XvQTaSsT8Qnj6PigfFu80ee1q9hBZ2AZDxkajczfeYIb 4HhWw/DB60DnwObbiUVXoPBRUvNnxNWQR3Ii5FGqv3DJICf1SYb+iqnAUjxgIrMlFy bzWO5O81FgSpw== From: Sasha Levin To: imre.deak@intel.com, luciano.coelho@intel.com Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] drm/i915/dp_mst: Fix configuring TUs for a disconnected stream" failed to apply to 5.15-stable tree Date: Sat, 7 Nov 2026 05:58:57 -0500 Message-ID: <20261107055857-failed-5.15-ee00f8fbb2b2@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x ee00f8fbb2b202002ab90834e02e9ba372773a36 # git commit -s git send-email --to '' --in-reply-to '20261107055857-failed-5.15-ee00f8fbb2b2@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From ee00f8fbb2b202002ab90834e02e9ba372773a36 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Mon, 7 Sep 2026 20:44:13 +0300 Subject: [PATCH] drm/i915/dp_mst: Fix configuring TUs for a disconnected stream During an atomic commit after all the MST stream CRTC state is computed the driver ensures that the sum of TUs of all the streams on a given MST topology link is within limits (63 for 8b10 and 64 for 128b132b). For a disconnected stream the DRM MST core's BW verification doesn't ensure this, because the topology state it uses for this is destroyed as soon as the stream (i.e. MST connector/port) is disconnected. The driver should keep the link state valid even for such disconnected streams, as userspace may disable them one-by-one only in a deferred way. Ensure the link's sum of TUs stays within limits in this case by simply reusing the maximum link BPP limit from the stream's (i.e. CRTC's) old state. The disconnection can happen either via the whole topology getting disconnected or via only the given stream's port getting disconnected. Check for both of these conditions separately, as a connector gets unregistered after a link disconnect event only in a deferred way. Cc: stable@vger.kernel.org # v6.10+ Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16073 Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16384 Reviewed-by: Luca Coelho Signed-off-by: Imre Deak Link: https://patch.msgid.link/20260907174413.741851-2-imre.deak@intel.com --- drivers/gpu/drm/i915/display/intel_dp_mst.c | 21 ++++++++++++++++++++ drivers/gpu/drm/i915/display/intel_dp_mst.h | 2 ++ drivers/gpu/drm/i915/display/intel_link_bw.c | 3 ++- 3 files changed, 25 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 20766b6c0bcfa..0c362784afe4a 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -2172,6 +2172,27 @@ bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state, return false; } +bool intel_dp_mst_stream_disconnected(struct intel_atomic_state *state, + const struct intel_crtc *crtc) +{ + struct intel_connector *connector; + + connector = get_connector_in_state_for_crtc(state, crtc); + if (!connector) + return false; + + if (!connector->mst.dp) + return false; + + if (!connector->mst.dp->mst.mgr.mst_state) + return true; + + if (drm_connector_is_unregistered(&connector->base)) + return true; + + return false; +} + /** * intel_dp_mst_prepare_probe - Prepare an MST link for topology probing * @intel_dp: DP port object diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h index ab09b487c6bb5..8ce89242c05c9 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.h +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h @@ -28,6 +28,8 @@ int intel_dp_mst_atomic_check_link(struct intel_atomic_state *state, struct intel_link_bw_limits *limits); bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state, struct intel_crtc *crtc); +bool intel_dp_mst_stream_disconnected(struct intel_atomic_state *state, + const struct intel_crtc *crtc); void intel_dp_mst_prepare_probe(struct intel_dp *intel_dp); bool intel_dp_mst_verify_dpcd_state(struct intel_dp *intel_dp); diff --git a/drivers/gpu/drm/i915/display/intel_link_bw.c b/drivers/gpu/drm/i915/display/intel_link_bw.c index b47474a3e9fec..e71e76d6fd3e0 100644 --- a/drivers/gpu/drm/i915/display/intel_link_bw.c +++ b/drivers/gpu/drm/i915/display/intel_link_bw.c @@ -64,7 +64,8 @@ void intel_link_bw_init_limits(struct intel_atomic_state *state, intel_atomic_get_new_crtc_state(state, crtc); int forced_bpp_x16 = get_forced_link_bpp_x16(state, crtc); - if (state->base.duplicated && crtc_state) { + if ((state->base.duplicated && crtc_state) || + intel_dp_mst_stream_disconnected(state, crtc)) { limits->max_bpp_x16[pipe] = crtc_state->max_link_bpp_x16; if (intel_dsc_enabled_on_link(crtc_state)) limits->link_dsc_pipes |= BIT(pipe); -- 2.53.0