From nobody Mon Jun 8 16:30:31 2026 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (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 D0E40233923 for ; Thu, 28 May 2026 07:05:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.180.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779951960; cv=none; b=KQQ4J1g8pcWA5LtrXUQ1yGGlBP6wpRI6as38huXBLgcoD4PcDhFkvFwFi+5HzkG7fyM9NvANGWR/XWZoHy7ypxz0ozHnFH0+l3DDXyh0pNsu1X5UvmisCaVgJbOpgfpPyD2fxor5gVWB4jKCbTvSciOEjC+n2Spffd83VHOGuAc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779951960; c=relaxed/simple; bh=6l8wxJF78Sm1qsTECaxMR9Jxhn223y61PPSh2SXZlS0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=pU/z6+qryLkZVmKEx09G/eRenE8Q7qaAFtErdkNVtaQkR0Z44X7VLFvKcx/RfrxWBlZ5Em7D3skaUIY3f3FR+0bg0Od7x9ID1C4snkhs9UeGZHx3XkCJ6S87r84yokkpGOaC+MQH3fQhEdAjBkdxPsQ+in/87sxhIeSAd3ny3Xg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b=bgPYNmfQ; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b=BhsT5a43; arc=none smtp.client-ip=205.220.180.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b="bgPYNmfQ"; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b="BhsT5a43" Received: from pps.filterd (m0279871.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 64RKlKjs2463183 for ; Thu, 28 May 2026 07:05:58 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to; s=qcppdkim1; bh=Zn6MXtkf9VBJ8MXm0zIEgP KH57WoIwNAFOEHdnwNHIc=; b=bgPYNmfQMbjVL09cnXhdpMohLOhH+CCcQ0k/ap +1M1nLQVRAxexVFW2mfewS+0zEpvMH8aChUnN1/DmfUhWttXNnnxDvQrrz/Q44gh T9hbhMTiEcQJSXIq/5OEnTl4TWrc0Dno3lJI0l1VDndJhN9LrsPXjkWEuyrb+9xP e5jqn4jiV3UcZSgRRhnR3hqE/AaWc3VgWO6jbsjxc8BRKx+XxbEl4ah9RC07A+qj YuJIzrYrvQkEEAzggRQugkYQ5CUOS+LG+1NFn7KQp0O+8d+sDO06tXcWMcaBtG2w Yc/Oh+UOLRpl/s50ToAFo3LmQFfMTvfnONENljb07Ap2P1uQ== Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4ee7y4spq0-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Thu, 28 May 2026 07:05:57 +0000 (GMT) Received: by mail-pf1-f197.google.com with SMTP id d2e1a72fcca58-82fa860e71eso6414652b3a.0 for ; Thu, 28 May 2026 00:05:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1779951957; x=1780556757; darn=vger.kernel.org; h=cc:to:message-id:content-transfer-encoding:mime-version:subject :date:from:from:to:cc:subject:date:message-id:reply-to; bh=Zn6MXtkf9VBJ8MXm0zIEgPKH57WoIwNAFOEHdnwNHIc=; b=BhsT5a43gUVLEYbnN1XcHr1BP3HdyAQU59u/yF0GosDvh8U7uMTRj+HtO0vOk7f7Iw VWb8ZViuQ2bf1hr2FIq68mnvyBV5JTGj3YOsKLxGtC+sRuBANzoMpV9wI9xr9M7lJyLA 9Ua/oABJVBFaR1w8jqGXVMOxHjOA9NW/O6AGoZXzP7aLFbH6ql2fX6lDXEW1Vkxnc7WR VrxiiyfeVC3Nv/lApBDYQZ/bVKrbUgSDxKgkebq6j/l1xw1Eg7C+uQjX8YZNLomyhEqw MkCy1acT4d8NPCGEjQj0aUuN+YFneV769nufYWEu5S4sH3Qj6eoK2p6Nvdae+NcXaNix tXIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779951957; x=1780556757; h=cc:to:message-id:content-transfer-encoding:mime-version:subject :date:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Zn6MXtkf9VBJ8MXm0zIEgPKH57WoIwNAFOEHdnwNHIc=; b=G+X2oibVZK4ROZ4FkZR0y2wUFgQli9uEOQtwIHzn+TcyXx7slBAcj5JaXw4cyik3W+ 0LZOzzvZfBRYiTgLZAP5YDhV4D2OIzoOpWVrTtV7u3lmlUWp382G33Y6+Xsq3bXLVOBw nkhYJYs/aKD5hXe0G++H+O5QnDCgQ+lpSeZ6BqbbzI+7SxfHSPmozi5e6sAHpjXMEqME mXyvGaKWcEv4CNJV5S4jPnSUtPw3ObT1gUensrecHdmXLArCA5ZBwn9huC25642HtWdw m+cHMqEh9xtXAuEXwLeMMtN3cICq8zuWznuVwQURv3cnmC8xdi4cyKIGmsrmbpXFQMv2 TZvA== X-Forwarded-Encrypted: i=1; AFNElJ8mwmzVTJuY/HCq3a/bMvYdVJx4uiiUuLmd4B+T0eqYtXc27JLaQbKOkwY1ThY4kzgRvhoaUwomCtZb3Io=@vger.kernel.org X-Gm-Message-State: AOJu0YxnLq3HYG57rCqFIGjzSFwPWA0BruN0M0OALu+s18TeZVUSNMZS Zh5SIBbE3IzYkAyd0xBi07i8s9uHg/GKE0GgxSA0eA9a8J9lXehhpYpL5MP93NH8GLRv5m6T34z gBCTDNESDCLK0FNKIYsdN6WEUO1Pb4G1NjHtnxvvkT5GCNSNtABKisVTirigdjyR3D84= X-Gm-Gg: Acq92OH3fKywq12/yY5RiP97fHgw2FAAQlsTR5z42qeW7oXkyyMYRtRp2CoiTN036Lk 2UPOsiW2guX079BrB7pqM35dYxEFKyRGktUo4DM2KUo2VtjxBWPhuhfXqOeJPoUFjvyWHMOBR+m 0WmFzzMPwVGOtYdvIky68GbcgMhPMCygsP5D3xlR559BpfEdaaQfcbhGu+m2i2IYvRkrCRAJOpJ Jrkkow7doTBQk7EjQ65Y8UCstDiJRFE2tiBJecPyVFPViHDdbht6PkS7M0stXt4vefqjmLFPNS2 zS99K09EtZjAlELAu1rplXPHX4l4YHDxnTTPOigpXkZVKNXbcb8+O9H0eRHZf072BNvFD8nXkz4 wIKPXaOoaZq9xYF+cznEiz3QgAgQQG4weFC+nnK6uRR+TTz1+xwhWd1hsqsHwGONGcVAT X-Received: by 2002:a05:6a00:14c8:b0:82f:559d:ece3 with SMTP id d2e1a72fcca58-8415f32d5ffmr23009161b3a.15.1779951956708; Thu, 28 May 2026 00:05:56 -0700 (PDT) X-Received: by 2002:a05:6a00:14c8:b0:82f:559d:ece3 with SMTP id d2e1a72fcca58-8415f32d5ffmr23009126b3a.15.1779951956049; Thu, 28 May 2026 00:05:56 -0700 (PDT) Received: from hu-vdadhani-hyd.qualcomm.com ([202.46.23.25]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-841d6ed19c2sm3992512b3a.25.2026.05.28.00.05.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 May 2026 00:05:55 -0700 (PDT) From: Viken Dadhaniya Date: Thu, 28 May 2026 12:35:43 +0530 Subject: [PATCH v1] serial: qcom_geni: Fix RX DMA stall when SE_DMA_RX_LEN_IN is zero Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260528-serial-rx-0-byte-fix-v1-1-dc4e876c7368@oss.qualcomm.com> X-B4-Tracking: v=1; b=H4sIAEbpF2oC/yWMQQqDMBREryKz7ocYqKa9SulC46i/FFsSFYt4d 2NdvsfMWxEZlBH3bEXgrFE/Q4L8ksH31dBRtEkMa2xhrtbJsa/eEhYxUv9GSquL0N8a43zL0hH p+g1M+p99YM7xPF2c6hf9ePSwbTuPFbeTfAAAAA== X-Change-ID: 20260528-serial-rx-0-byte-fix-ec9d08cfe78e To: Greg Kroah-Hartman , Jiri Slaby , Bartosz Golaszewski Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Viken Dadhaniya X-Mailer: b4 0.16-dev X-Developer-Signature: v=1; a=ed25519-sha256; t=1779951953; l=1800; i=viken.dadhaniya@oss.qualcomm.com; s=20260324; h=from:subject:message-id; bh=6l8wxJF78Sm1qsTECaxMR9Jxhn223y61PPSh2SXZlS0=; b=+CUlkAPdkKpET1LGpF5QcG9RbMucMjNy+72nXZrNy/joe/1WCcEiyd+WIKFK/dhG8m1LZO3gg DHChh8zKlLeBWOrV6AqXRlusZMnA5WxJtbt3mC0ryM/paua7rVKMIip X-Developer-Key: i=viken.dadhaniya@oss.qualcomm.com; a=ed25519; pk=C39f+LOIGhh/02LQpT46TsUSXRvBn9qXC8Xb26KJ44Y= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTI4MDA2OCBTYWx0ZWRfXxaZXCpCpiDkC ICGhpAqCuJZ2Qo0WKfpFQyD/CF8w+9JVY66DKtCjKUX7bNfx8bBf6+JK+a6m39sFgCD1ZNrknz8 OscjE205oK+onhldg5rDkGWsP1zasnVn+HzXHJnyv3KusQOWcT+07+ya2vaIZVOw3T0I7cqBYm4 4IpepoWftQU2wN+8b6PmLYkEQfPBQtHBDg68asmvLrOD1iygLnH1B7hFtivveifY5+lpFbG68Im DlZ4x/6pGrGgdK4pNP2aXcRf7114AYLuxiDwYDp5c//htBoUWXzsvcYXOPFbyQghP+mAoOVV+Va THzUubvkMtky1cBXG7du0pkZYtEC7y42og3M63M31/x8S3HVJnNCBgJdc+tuLawI9VHOOgyBz54 hCVUwm1M8VS07ORFfL+7F/V8kIyZS5pYGHb5W8Ogl6j7WIRmhlpzJAhldYgbcynp6VF3NWV3uHF QFtfbqMNRFq2Su6wuig== X-Authority-Analysis: v=2.4 cv=feidDUQF c=1 sm=1 tr=0 ts=6a17e955 cx=c_pps a=rEQLjTOiSrHUhVqRoksmgQ==:117 a=ZePRamnt/+rB5gQjfz0u9A==:17 a=IkcTkHD0fZMA:10 a=NGcC8JguVDcA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=3WHJM1ZQz_JShphwDgj5:22 a=EUspDBNiAAAA:8 a=e3_-XpViw8z6FsUMn4gA:9 a=QEXdDO2ut3YA:10 a=2VI0MkxyNR6bbpdq8BZq:22 X-Proofpoint-GUID: LvMtDWh-Ytkkg-tWtQ52zD-tNxt8Yd_g X-Proofpoint-ORIG-GUID: LvMtDWh-Ytkkg-tWtQ52zD-tNxt8Yd_g X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-05-28_02,2026-05-26_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 spamscore=0 priorityscore=1501 phishscore=0 suspectscore=0 bulkscore=0 impostorscore=0 adultscore=0 lowpriorityscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2605280068 In qcom_geni_serial_handle_rx_dma(), geni_se_rx_dma_unprep() clears port->rx_dma_addr before SE_DMA_RX_LEN_IN is read. If the register is zero, for example when the RX stale counter fires on an idle line, the handler returns without calling geni_se_rx_dma_prep(). The next RX DMA interrupt then hits the !port->rx_dma_addr guard and returns immediately, so the RX DMA buffer is never rearmed and later input is lost. Keep the handler on the rearm path when rx_in is zero. Warn about the unexpected zero-length DMA completion, skip received-data handling, and always call geni_se_rx_dma_prep(). Fixes: 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial= engine DMA") Signed-off-by: Viken Dadhaniya Reviewed-by: Bartosz Golaszewski --- drivers/tty/serial/qcom_geni_serial.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qco= m_geni_serial.c index d81b539cff7f..7ead87b4eb65 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -905,12 +905,9 @@ static void qcom_geni_serial_handle_rx_dma(struct uart= _port *uport, bool drop) port->rx_dma_addr =3D 0; =20 rx_in =3D readl(uport->membase + SE_DMA_RX_LEN_IN); - if (!rx_in) { - dev_warn(uport->dev, "serial engine reports 0 RX bytes in!\n"); - return; - } - - if (!drop) + if (!rx_in) + dev_warn_ratelimited(uport->dev, "serial engine reports 0 RX bytes in!\n= "); + else if (!drop) handle_rx_uart(uport, rx_in); =20 ret =3D geni_se_rx_dma_prep(&port->se, port->rx_buf, --- base-commit: e7d700e14934e68f86338c5610cf2ae76798b663 change-id: 20260528-serial-rx-0-byte-fix-ec9d08cfe78e Best regards, -- =20 Viken Dadhaniya