From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Reichel Subject: Re: [PATCH 15/15] tty: serial: 8250: omap: add dma support Date: Tue, 2 Sep 2014 22:38:35 +0200 Message-ID: <20140902203834.GA7050@earth.universe> References: <20140827202313.GF16006@atomide.com> <20140828082348.GA5413@linutronix.de> <20140828164645.GG16006@atomide.com> <53FF84DF.7080406@linutronix.de> <20140828225454.GM16006@atomide.com> <540048B4.7010807@linutronix.de> <20140829161221.GO16006@atomide.com> <5404B149.6010400@linutronix.de> <54060EDA.6060204@linutronix.de> <20140902201536.GC11766@atomide.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="sdtB3X0nJg68CQEu" Return-path: Content-Disposition: inline In-Reply-To: <20140902201536.GC11766@atomide.com> Sender: linux-omap-owner@vger.kernel.org To: Tony Lindgren Cc: Sebastian Andrzej Siewior , balbi@ti.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Vinod Koul , Greg Kroah-Hartman , Paul Walmsley List-Id: linux-serial@vger.kernel.org --sdtB3X0nJg68CQEu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 02, 2014 at 01:15:37PM -0700, Tony Lindgren wrote: > * Sebastian Andrzej Siewior [140902 11:40]: > > On 09/01/2014 07:47 PM, Sebastian Andrzej Siewior wrote: > > > Comparing it with serial-omap I see the same thing: I takes approx the > > > same amount of data until the first one is displayed. After a lot of > > > "long" writes which wake the chip up from idle I manage to freeze bot= h, > > > the serial-omap driver and mine driver. > >=20 > > So after some testing: > > - it happens with omap-serial as well. Especially after disabling the > > LED trigger for both LEDs. > >=20 > > - it seemed that disabling the MDR1 check whether or not we lost > > context made the problem appear less often but it was a trick. Even > > with restoring the context each time I see the same problem. > >=20 > > - it seems to be easier to trigger with the LED trigger switched off. > > However sometimes it works for 10 minutes, sometimes it triggers > > after one. > >=20 > > - I see to face two kind of "deaths": > > - the LED still goes on and off and the uart just does not respond > > even if I tell the button print something on the screen (the button > > also changes the frequency of the LED so I know that the button is > > doing something). > > Also from dumping the content of /proc/interrupts it seems that a > > wake up is made, the uart should have restored the registers. >=20 > OK yeah this is the case I was seeing too. So do you just set the > LED triggers to none in sysfs to make it easier to reproduce? >=20 > > - one where the system is dead and the LED does not blink anymore. > > Also my button is dead. >=20 > This I don't think I've seen. This could also be the errata issue on > your earlier rev beagleboard-xm with off-idle. > =20 > > - disabling DMA makes the problem not go away. >=20 > OK > =20 > > - mdelay(25) in omap8250_lost_context() is long enough to drop the 403 > > bytes I send in my testcase. That means I see only "good" characters. > > With this the box remained alive for 2h. However the uart died anyway. >=20 > I wonder if doing some TX on the uart restores it? So maybe try >=20 > $ while [ 1 ]; do date; sleep 10 done & >=20 > To have it occasionally print something in the background. If there is a way to detect the hangup you may try to recover by resetting the serial device using omap_hwmod_reset(). -- Sebastian --sdtB3X0nJg68CQEu Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJUBirKAAoJENju1/PIO/qaCIgP/Rds/S7BGi6+vDjkYjvjnAC4 WFCthw8g084rktqWOxZXg4HyCRVTnFpPvrxcurEOtZZSFacvR/e+v1ZObLqJ12O6 75xRgMTSAOY9tzxe62Sq4Gqmf07Gdu8iqSlkk5eAUOAXRRsehaMFMJNxK+MVnczA HZY5ZKbEv9C43GyDL2TaCEn4q/9q35qY9/TcdTPO9rJNUg6SVQkcCf0ixxgfqBkk C17XD050YRyWdonh7hL5ZJY1GhdHDXN4ZJtzQXkDLfNPu3noq1SqubNfvWsU1KzB HVW/QKvc4uyoThotbF7ZSa3JYfpB0+m7Y6I0rGgDfxVCKBBjD1MKbUUlyjQdHPGf dC03A0NCJmTSvUUs1/86QgpgiGBWAPi2GxMuSw3+PklbNfrCRmzG4ykRa7J+6Ini kpjKpDOmj6S70T+bO6lv+8KjnPr8Wn32gK3YvHVZ22VP8Lx1wm+3cmn6T9AFXSYE f3w7TbGND8b8xeDir6kbUBLAfcZpAuUme1R74WRXehkw2l3q05iMURWkm7ZgJwHS SqszW0qhnX2+IIPecH2g7LHu0LNzO1rfm3vOhV/o7RHN6shtX481KONPEkzXELM2 Ldisg4gyXI5s3EfAJjMMsSEibTqoSbeYZXtrM3fq4kmkhZfSaeSdN+Nyz7YLuT2A xcY1vmkekO+4ju2oXo+0 =hCWF -----END PGP SIGNATURE----- --sdtB3X0nJg68CQEu--