[PATCH v3] Revert "serial: 8250_dma: don't bother DMA with small transfers"

[Frederic Danis <frederic.danis@linux.intel.com>]

This reverts commit 9119fba0cfeda6d415c9f068df66838a104b87cb.

This commit prevents from sending "big" file using Bluetooth.
When sending a lot of data quickly through the Bluetooth interface, and
after a variable amount of data sent, transfer fails with error:
    kernel: [  415.247453] Bluetooth: hci0 hardware error 0x00

Found on T100TA.

After reverting this commit, send works fine for any file size.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Fixes: 9119fba0cfed (serial: 8250_dma: don't bother DMA with small
transfers)
Cc: stable@vger.kernel.org
---
v3: Add Fixes and Cc tags
v2: Re-send to correct people

 drivers/tty/serial/8250/8250_dma.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index b503071..78259d3 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -77,10 +77,6 @@ int serial8250_tx_dma(struct uart_8250_port *p)
 		return 0;
 
 	dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
-	if (dma->tx_size < p->port.fifosize) {
-		ret = -EINVAL;
-		goto err;
-	}
 
 	desc = dmaengine_prep_slave_single(dma->txchan,
 					   dma->tx_addr + xmit->tail,
-- 
1.9.1