| Message ID | 20230307164405.14218-4-johan+linaro@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | serial: qcom-geni: fix console shutdown hang | expand |
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2aa3872e6283..9871225b2f9b 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -631,6 +631,9 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport) if (port->tx_dma_addr) return; + if (uart_circ_empty(xmit)) + return; + xmit_size = uart_circ_chars_pending(xmit); if (xmit_size < WAKEUP_CHARS) uart_write_wakeup(uport);
Make sure that there is data in the ring buffer before trying to set up a zero-length DMA transfer. This specifically fixes the following warning when unmapping the empty buffer on the sc8280xp-crd: WARNING: CPU: 0 PID: 138 at drivers/iommu/dma-iommu.c:1046 iommu_dma_unmap_page+0xbc/0xd8 ... Call trace: iommu_dma_unmap_page+0xbc/0xd8 dma_unmap_page_attrs+0x30/0x1c8 geni_se_tx_dma_unprep+0x28/0x38 qcom_geni_serial_isr+0x358/0x75c Fixes: 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> --- drivers/tty/serial/qcom_geni_serial.c | 3 +++ 1 file changed, 3 insertions(+)