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 4722B2D5412; Thu, 25 Jun 2026 13:08:39 +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=1782392921; cv=none; b=Tk5LwcXYFua6RdybCTHoviE1/AfCAny0My9FoAikfE9FDboAlSSJBp3Pr8UTivcfr3d6xsgKzb8mOuspxt4uOsqI1vVB2u0G8Xi3xdU1eYrwEEgZeo+wqI48CiZs97n4bnA+DosxVm2ozMv1p/GBMec57T0XpjeSn2ol0hfVarc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782392921; c=relaxed/simple; bh=qkkdZO9y4eI9YWUbq0eIexhWNlQgx6suOjZwY3Z73VM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f/xQpQRQxJy4Ojg2iyRzuzQnvvr7N6h2eSeC42oTkRKsY6ayV+IWkil4KOx35F/eKIjmfsfZmkQvdpcEUj+0ZcJr3YXc0dHD/c0Lx2OtO0MQ3seJnn0CgJvMXRdr5BumQguCxstizvZqyo9P5j2o/AxaEzI6VJpLhWrkfARFoK8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wvl+woJZ; 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="wvl+woJZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71F591F000E9; Thu, 25 Jun 2026 13:08:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782392919; bh=6z+AJt0/KBOWHLWnl1TLFkbEoB5OYQy606dx0tCJwoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=wvl+woJZlbZl8VFcRppmgknvMyGIqxUtiIGiaLAcLBiSp5TrlSRp0/RwMyEKGXp0N aqc/iWNlDBea2T7QzcBGWA11Jlops46g2Z21gSkPM4DgedsC91ZLYqDZtoE9SCYX+v bLYsX1wBs1J5AqNAbzwPBFY6GMJwErw5oSoakHZo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bartosz Golaszewski , Viken Dadhaniya Subject: [PATCH 6.18 55/60] serial: qcom_geni: Fix RX DMA stall when SE_DMA_RX_LEN_IN is zero Date: Thu, 25 Jun 2026 14:03:40 +0100 Message-ID: <20260625125653.771532369@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260625125645.554579168@linuxfoundation.org> References: <20260625125645.554579168@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Viken Dadhaniya commit b93062b6d8a1b2d9bad235cac25558a909819026 upstream. 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") Cc: stable@vger.kernel.org Reviewed-by: Bartosz Golaszewski Signed-off-by: Viken Dadhaniya Link: https://patch.msgid.link/20260528-serial-rx-0-byte-fix-v2-1-b4195cfe342f@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -896,12 +896,9 @@ static void qcom_geni_serial_handle_rx_d port->rx_dma_addr = 0; rx_in = 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); ret = geni_se_rx_dma_prep(&port->se, port->rx_buf,