From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: DSS2/PM on 3.2 broken? Date: Thu, 19 Jan 2012 07:30:32 +1100 Message-ID: <20120119073032.74cc0992@notabene.brown> References: <20120110080849.5a242adf@notabene.brown> <20120112095940.0a54413e@notabene.brown> <20120113222045.37f9b4ec@notabene.brown> <1326870839.1954.23.camel@deskari> <20120118221538.342b4782@notabene.brown> <1326886940.1999.5.camel@lappy> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/rZ+3vNSkCEP8NqH5FS=Wc8M"; protocol="application/pgp-signature" Return-path: Received: from cantor2.suse.de ([195.135.220.15]:51273 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757202Ab2ARUap (ORCPT ); Wed, 18 Jan 2012 15:30:45 -0500 In-Reply-To: <1326886940.1999.5.camel@lappy> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tomi Valkeinen Cc: Paul Walmsley , Joe Woodward , khilman@ti.com, t-kristo@ti.com, govindraj.r@ti.com, linux-omap@vger.kernel.org --Sig_/rZ+3vNSkCEP8NqH5FS=Wc8M Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 18 Jan 2012 13:42:20 +0200 Tomi Valkeinen wrote: > On Wed, 2012-01-18 at 22:15 +1100, NeilBrown wrote: > > On Wed, 18 Jan 2012 09:13:59 +0200 Tomi Valkeinen > > wrote: > >=20 > > > On Fri, 2012-01-13 at 22:20 +1100, NeilBrown wrote: > > > > Having CPUIDLE makes the DSS2 problem worse: lots of=20 > > > >=20 > > > > [ 21.085113] omapdss DISPC error: SYNC_LOST on channel lcd, > > > > restarting the output with video overlays disabled > > > >=20 > > > > messages whenever the CPU isn't busy. > > >=20 > > > I'm not sure if it is the case here, but DSS has restrictions about t= he > > > max DSS clocks on different OPPs. For example, on OMAP4430 LCD clock > > > maximum is 186MHz at OPP100, and 93MHz at OPP50. So it's a quite big > > > drop, causing problems with all but the rather small displays. > > >=20 > > > And the DSS driver doesn't have any support to handle this at the > > > moment, as there isn't support in the PM framework to do this. I think > > > the only way to handle this at the moment is for the DSS driver to set > > > an arbitrarily high constraint on, say, mem throughput, and hope that= it > > > keeps the OMAP in the required OPP. > > >=20 > > > Tomi > > >=20 > >=20 > > This LCD panel on this device sets: > > .pixel_clock =3D 22000, > > in the "struct omap_video_timings" so I'm guessing that is 22MHz? >=20 > No, that's the pixel clock. There are probably limitations on the pix > clock also, but usually the problem is the functional clocks, which need > to be n x pck, where n depends on the needs for scaling. Ahh.. cat /sys/kernel/debug/omapdss/clk is below and reports 66461538 for fck, so 66MHz? Still safe for OPP50. And disabling SMART REFLEX had no obvious effect. If you can think of anything else I could try to explore to narrow down=20 the source of this, I am very happy to test or examine anything you suggest. Thanks, NeilBrown - DSS - dpll4_ck 864000000 DSS_FCK (DSS1_ALWON_FCLK) =3D 864000000 / 13 =3D 66461538 - DISPC - dispc fclk source =3D DSS_FCK (DSS1_ALWON_FCLK) fck 66461538 =20 - LCD1 - lcd1_clk source =3D DSS_FCK (DSS1_ALWON_FCLK) lck 66461538 lck div 1 pck 22153846 pck div 3 - DSI1 PLL - dsi pll source =3D pclkfree Fint 0 regn 0 CLKIN4DDR 0 regm 0 DSS_FCK (DSS1_ALWON_FCLK) 0 regm_dispc 0 (off) DSS_FCK (DSS1_ALWON_FCLK) 0 regm_dsi 0 (off) - DSI1 - dsi fclk source =3D DSS_FCK (DSS1_ALWON_FCLK) DSI_FCLK 66461538 DDR_CLK 0 TxByteClkHS 0 LP_CLK 0 --Sig_/rZ+3vNSkCEP8NqH5FS=Wc8M Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBTxcr6Dnsnt1WYoG5AQLgLBAAnyIh95Zk2sWK8fX2UheW4d0YQ1UHLnsH KJRRazLXq5xe+Uu9naCGPb3j2guvwmESkX6u6L0xlxM6kjyBt+dwBzcfC1Tmmwm1 wUfTmTqGmIiBonffd+kaSpGZEwrScM+TbPIxtXElx/jzVoXaDeKP+YoXdgO1Gg7x mUwF6J7mybjwskxw/jwEW59CYkuRV13FBj7yBxs3en6ArKy9sYAhtixYr4Qni3vV VB+6v7uSuM9tWZX0vnFSsAMuRbLojQKqwZTIzRVgmfqSvgVap7QpyJcarXCnKpH7 Hng+EmtsYQXwzNsVDHGkTxT84AktjZ6HBPBO7MJuxSkAYKInWYEJsLJgj2l+gqn5 MqkGVEc45QDNGL/Wn18iKK9/Qw4vnwjDFb3Kp2tjVq2pzE3psuurL890elTKKMlE NnUHprJk+6ZzqLkf+Wit1x6STJ/tcKRu40QAq0JXBTdI2oTlyMP1mjTktUk4nD2r XSlexyEA91p+ee5N5bMM4IHm4mIMg2CaS87j6PmpySW8NuV8/r+36Hfcb67s+tpl oPufcLd6GzzHd89Hzru4QYk6wuBjRJDomt9gcxYHV+GHKdcaKAt0L8V5IbVtsvsm FzG2xNaM65xNdgpamE0Tf2r3Oy+O/aRxgkQ7szsXyZ906BzxGhvHU4LNsI79UfAC liXTAPzmChU= =Mcao -----END PGP SIGNATURE----- --Sig_/rZ+3vNSkCEP8NqH5FS=Wc8M--