5.15-stable review patch. If anyone has any objections, please let me know.
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From: Ronald Wahl ronald.wahl@raritan.com
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@vger.kernel.org Fixes: c26389f998a8 ("serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs") Signed-off-by: Ronald Wahl ronald.wahl@raritan.com Reviewed-by: Vignesh Raghavendra vigneshr@ti.com Link: https://lore.kernel.org/r/20231101171431.16495-1-rwahl@gmx.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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) {