On 01/11/23 22:44, Ronald Wahl wrote:
> From: Ronald Wahl <ronald.wahl@xxxxxxxxxxx>
>
> Starting RX DMA on THRI interrupt is too early because TX may not have
> finished yet.
>
> This change is inspired by commit 90b8596ac460 ("serial: 8250: Prevent
> starting up DMA Rx on THRI interrupt") and fixes DMA issues I had with
> an AM62 SoC that is using the 8250 OMAP variant.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: c26389f998a8 ("serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs")
> Signed-off-by: Ronald Wahl <ronald.wahl@xxxxxxxxxxx>
> ---
> V4: - add missing braces to fix build warning
>
> V3: - add Cc: stable@xxxxxxxxxxxxxxx
>
> V2: - add Fixes: tag
> - fix author
>
> drivers/tty/serial/8250/8250_omap.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
> index c7ab2963040b..1122f37fe744 100644
> --- a/drivers/tty/serial/8250/8250_omap.c
> +++ b/drivers/tty/serial/8250/8250_omap.c
> @@ -1282,10 +1282,12 @@ static int omap_8250_dma_handle_irq(struct uart_port *port)
>
> status = serial_port_in(port, UART_LSR);
>
> - if (priv->habit & UART_HAS_EFR2)
> - am654_8250_handle_rx_dma(up, iir, status);
> - else
> - status = omap_8250_handle_rx_dma(up, iir, status);
> + if ((iir & 0x3f) != UART_IIR_THRI) {
> + if (priv->habit & UART_HAS_EFR2)
> + am654_8250_handle_rx_dma(up, iir, status);
> + else
> + status = omap_8250_handle_rx_dma(up, iir, status);
> + }
Reviewed-by: Vignesh Raghavendra <vigneshr@xxxxxx>
Thanks for the fix!
>
> serial8250_modem_status(up);
> if (status & UART_LSR_THRE && up->dma->tx_err) {
> --
> 2.41.0
>
--
Regards
Vignesh
