From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi Subject: Re: [RFC PATCH 3/4] tty: omap-serial: use threaded interrupt handler Date: Wed, 20 Aug 2014 11:06:05 -0500 Message-ID: <20140820160604.GH24500@saruman.home> 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> <20140819185701.GC22003@saruman.home> <20140820064028.GC9319@ci00147.xsens-tech.local> Reply-To: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9sSKoi6Rw660DLir" Return-path: Content-Disposition: inline In-Reply-To: <20140820064028.GC9319@ci00147.xsens-tech.local> Sender: linux-serial-owner@vger.kernel.org To: Frans Klaver Cc: Felipe Balbi , Tony Lindgren , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Greg Kroah-Hartman , Alexey Pelykh , Jiri Slaby , Frans Klaver , linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org --9sSKoi6Rw660DLir Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 20, 2014 at 08:40:28AM +0200, Frans Klaver wrote: > 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: > > > At 3.6Mbaud, with slightly over 2Mbit/s data coming in, we see 1600 u= art > > > rx buffer overflows within 30 seconds. Threading the interrupt handli= ng reduces > > > this to about 170 overflows in 10 minutes. > >=20 > > Can you try Sebastian Siewior's patches for 8250_omap and 8250 dma > > support ? That should help you a lot. >=20 > I'll have a look at that series. Thanks for pointing it out. >=20 > > > drivers/tty/serial/omap-serial.c | 31 ++++++++++++++++++++++++------- > > > 1 file changed, 24 insertions(+), 7 deletions(-) > > >=20 > > > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/om= ap-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_por= t *up, unsigned int lsr) > > > } > > > =20 > > > /** > > > + * serial_omap_fast_irq() - schedule interrupt handling > > > + */ > > > +static irqreturn_t serial_omap_fast_irq(int irq, void *dev_id) > > > +{ > > > + struct uart_omap_port *up =3D dev_id; > > > + unsigned int iir =3D serial_in(up, UART_IIR); > > > + > > > + if (iir & UART_IIR_NO_INT) > > > + return IRQ_NONE; > > > + > > > + disable_irq_nosync(up->port.irq); > >=20 > > NAK. Either use IRQF_ONESHOT or actually mask the IRQs at the device's > > registers (basically clearing IER). >=20 > 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. if we find a way to maintain the same ttyO* naming scheme and make it coexist with ttyS* naming, then we could drop as soon as 8250_omap is ready for prime time. --=20 balbi --9sSKoi6Rw660DLir Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJT9MdsAAoJEIaOsuA1yqRE+i0P/jOlXZ6FiDz9F74YSnbjOYBY I9cIlhoosTWcknyS3AZKMtaU8/zyRbbeVwWNVPQrGyVK9q16LGMoV4YUdaYTeQnN /0WeviuSoDRBULEiKJEIahIbAtT5+ftMttYhX6MCqXvJvJTUyfOF7RIK4UdQ2NCd lqWa37dS9KKH0Po4YtL8i9ZcPWyUlrRFI5aw86Oos65BIvcH7F8AAfe24cXRAEMM QTd67cX5GR1TJCcm+znb0S2X5/PVd3BCleHdTRM9dODzX3xZYGQ/JtoH2ABCBCVb SW0dPHE49aYz6xcYms2cwe7bzF2axf2sQSROXMJZxKn75qa8E6UaHb9M6Q9DrtC+ f0jwlMmL917gZJGeT5GW4A7Aiq9kyk32spswRyEKgC4wDdFIdzO+Phpc23b6vl9u zyDEg0M/i8IAcbrK+K+aEvomCxP/dRB0CkcIbcthz4Eon8jUr+AzzbQzkrK0BbFA pbrJFf9ivAFh9uTLhnAb+551qDXBn1mpW9Ki/nVa0sD4lL53+lIfiufTGo9CNFmo tH59zqOXAEqZ/SLxAgNXRWnrAibHbUx46LFxD0d0nuA+GWieEjleci911RUgo+mr L69YQxz2Ldn4xw0EW2Vz3nN53SP3Kci28Uo2nrZzpv8r3nvxGcEICu9Dn/eG8rtb ufT1mIwqK2s82wyCcbpo =Dv3x -----END PGP SIGNATURE----- --9sSKoi6Rw660DLir--