On Tue, Aug 19, 2014 at 01:57:02PM -0500, Felipe Balbi wrote:

On Tue, Aug 19, 2014 at 02:14:47PM +0200, Frans Klaver wrote:

quoted

At 3.6Mbaud, with slightly over 2Mbit/s data coming in, we see 1600 uart
rx buffer overflows within 30 seconds. Threading the interrupt handling reduces
this to about 170 overflows in 10 minutes.

Can you try Sebastian Siewior's patches for 8250_omap and 8250 dma
support ? That should help you a lot.

I'll have a look at that series. Thanks for pointing it out.

quoted

 drivers/tty/serial/omap-serial.c | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 14a0167..57664b9 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c

@@ -575,6 +575,21 @@ static void serial_omap_rdi(struct uart_omap_port *up, unsigned int lsr)
 }
 
 /**
+ * serial_omap_fast_irq() - schedule interrupt handling
+ */
+static irqreturn_t serial_omap_fast_irq(int irq, void *dev_id)
+{
+	struct uart_omap_port *up = dev_id;
+	unsigned int iir = serial_in(up, UART_IIR);
+
+	if (iir & UART_IIR_NO_INT)
+		return IRQ_NONE;
+
+	disable_irq_nosync(up->port.irq);

NAK. Either use IRQF_ONESHOT or actually mask the IRQs at the device's
registers (basically clearing IER).

Given the work that's been done on the 8250 based driver, what are the
short-term chances omap-serial will be dropped? I'd be happy to improve
here if it makes sense to do so. If the 8250 based driver is going to
replace omap-serial anyway on the short term, I don't see the point of
further developing this patch. The others would still make sense in my
opinion.

Thanks,
Frans