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 C6009349CF2; Thu, 2 Jul 2026 16:52:16 +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=1783011137; cv=none; b=N3WMYmcx1mYEB59dqvnxjx+ce2x3aZu3xf/m+OeuRCQ1n/g1WpYQN+7YI0WcXr+PnuAyjDdrS6o75AjAHu3vuQJ8iJQcneofMkBkykWzAxVfQjZLn9tx7JdzE2Hmhn2le6CBMeMeHKePQN3xzZfRayH++s+S2L2Xz+AHSlARdQI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783011137; c=relaxed/simple; bh=32XukIrfM3SQFyj2bLDFztJq27xBYfWqlrFDmUuKkPA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MOTA+KvuXiY/aRL5fTyNxhTvQb2uaYE0ZwNSBe1fFKSF9JbmT5pqD0zGeGpQLf8jiRDzaRaDaoZU87qgFQIlY26yHtlvraktHQhQIDYTH8M3K4o4wp8In/O/GBIFOcOyP9UnV3VLF9lBvhbiysta8Xqkc1kdA5OyMPxgi5tsZd4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dNhNbopN; 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="dNhNbopN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 054B31F000E9; Thu, 2 Jul 2026 16:52:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783011136; bh=TBSQJBOQqteDfCdhyTnV4N0ITzF8AAS/2hROgzafjtc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dNhNbopNes5myoyrucdXhsVwp4Nfbx3N5KD8zX6Cu5CX5wPPGm4GegZntxWSFbxdw Cu4D6zj17K8nU8jAA0r5veqTS5pNXBRHRhdCNPzPXHfwQl1+uLKUJHyjnBNteU5wE0 lhrbZi3oBW3MmGhjNdtyOq2Nu37JCxvVsaxtUxWo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bartosz Golaszewski , Viken Dadhaniya , Sasha Levin Subject: [PATCH 6.6 169/175] serial: qcom_geni: Fix RX DMA stall when SE_DMA_RX_LEN_IN is zero Date: Thu, 2 Jul 2026 18:21:10 +0200 Message-ID: <20260702155119.345964034@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155115.766838875@linuxfoundation.org> References: <20260702155115.766838875@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Viken Dadhaniya [ Upstream commit b93062b6d8a1b2d9bad235cac25558a909819026 ] 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 Signed-off-by: Sasha Levin 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 @@ -838,12 +838,9 @@ 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, drop); ret = geni_se_rx_dma_prep(&port->se, port->rx_buf,