5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ronald Wahl <ronald.wahl@xxxxxxxxxxx>
commit c6bb057418876cdfdd29a6f7b8cef54539ee8811 upstream.
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>
Reviewed-by: Vignesh Raghavendra <vigneshr@xxxxxx>
Link: https://lore.kernel.org/r/20231101171431.16495-1-rwahl@xxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_omap.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -1203,10 +1203,12 @@ static int omap_8250_dma_handle_irq(stru
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);
+ }
serial8250_modem_status(up);
if (status & UART_LSR_THRE && up->dma->tx_err) {
