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 C115731F9A8; Thu, 2 Jul 2026 16:39:44 +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=1783010385; cv=none; b=bPISD4LtBxx88zG3Enp2gncg+X7gjwIMyu3V88twv45aJ+6/5+rTdpcZPQZ6WYWLPXiiad83s9u5cv9vD/iqxuXoy/PHTjkZ2Vv4LQLicDcxTj5FYAKA9JIBygfqmfjTXv0UcGOzC0oZnaEPY7Mx6I72xfzw85XNU9lKKbgh2uo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783010385; c=relaxed/simple; bh=WkoDwvBEIpAH0ug+mM9bHx/+HQfuaQ+hETW2a1dC0Ec=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BktzIcnMWS9LftGZ9LVeJBuiSVnwGwT2ZfLgnlwSmSrM+Z6Hx5Hp5c4/R9yLhWKNREjtgqPUZ/gMXZJvmanSYd1fVC6tGW/U2ztIpjiNfRyb395H8e7lNUm3f6Vu7bvDPTp0l7TD5+Nk4lErlRKSTk/y2GxL3m2kBRszUcSZRKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gfOnb9h8; 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="gfOnb9h8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33F1A1F000E9; Thu, 2 Jul 2026 16:39:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783010384; bh=nRl2SOKToStoO/BOFYLef1kZcWJC5sJhiqcCmFMjZsM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gfOnb9h8N35rL7HKSSkdrrHridBLKnPClwSkphcyR7cQrI1fJjndbHsYST9+oMBZM fhCN/mToNSAipdsOfFg/tH7TyOhdGRghjugQ0PL6lYHSsMc1oAu8qfZJU7WxJRksRA izav8xvSIc3f5YR7fT1hbtgZzg4nokO3YgI4dWcs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bartosz Golaszewski , Viken Dadhaniya Subject: [PATCH 6.12 089/204] serial: qcom_geni: Fix RX DMA stall when SE_DMA_RX_LEN_IN is zero Date: Thu, 2 Jul 2026 18:19:06 +0200 Message-ID: <20260702155120.531552693@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155118.667618796@linuxfoundation.org> References: <20260702155118.667618796@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 6.12-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 @@ -867,12 +867,9 @@ 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,