From mboxrd@z Thu Jan 1 00:00:00 1970 From: balbi@ti.com (Felipe Balbi) Date: Tue, 19 Aug 2014 13:57:02 -0500 Subject: [RFC PATCH 3/4] tty: omap-serial: use threaded interrupt handler In-Reply-To: <1408450488-4083-4-git-send-email-frans.klaver@xsens.com> References: <1406645577-18620-1-git-send-email-frans.klaver@xsens.com> <1408450488-4083-1-git-send-email-frans.klaver@xsens.com> <1408450488-4083-4-git-send-email-frans.klaver@xsens.com> Message-ID: <20140819185701.GC22003@saruman.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Aug 19, 2014 at 02:14:47PM +0200, Frans Klaver wrote: > 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. > In practice this therefore reduces the need for hardware flow control, > meaning the sending side doesn't have to buffer as much either. > > Signed-off-by: Frans Klaver > --- > 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). -- balbi -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: