From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: v3.4-rc4 DSS PM problem (Was: Re: Problems with 3.4-rc5) Date: Wed, 16 May 2012 12:20:01 +0300 Message-ID: <1337160001.7692.24.camel@deskari> References: <1336033721.14378.2.camel@deskari> <1336050442.14378.10.camel@deskari> <1336139415.2552.4.camel@deskari> <1336140072.2552.6.camel@deskari> <1336143281.2552.21.camel@deskari> <1336143500.2552.23.camel@deskari> <1336483598.5761.45.camel@deskari> <1336982138.2532.32.camel@lappyti> <1337159300.7692.22.camel@deskari> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-urjRnN/zoRZaA6wX7K4A" Return-path: Received: from na3sys009aog120.obsmtp.com ([74.125.149.140]:36542 "EHLO na3sys009aog120.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932936Ab2EPJUG (ORCPT ); Wed, 16 May 2012 05:20:06 -0400 Received: by lagw12 with SMTP id w12so343835lag.10 for ; Wed, 16 May 2012 02:20:03 -0700 (PDT) In-Reply-To: <1337159300.7692.22.camel@deskari> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Paul Walmsley Cc: Joe Woodward , khilman@ti.com, Archit Taneja , linux-omap@vger.kernel.org --=-urjRnN/zoRZaA6wX7K4A Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2012-05-16 at 12:08 +0300, Tomi Valkeinen wrote: > On Tue, 2012-05-15 at 11:55 -0600, Paul Walmsley wrote: > > Hello Tomi, > >=20 > > On Mon, 14 May 2012, Tomi Valkeinen wrote: > >=20 > > > I've been doing testing to understand the problem, but so far I don't > > > have any idea why things go wrong. I haven't found out any logic in > > > which configuration works and which doesn't. Looks to me that for som= e > > > reason the PM prevents DSS from getting data fast enough with certain > > > fifo thresholds. > > >=20 > > > I have two ways to avoid the problem, but I've been reluctant to make > > > patches for those because I feel it's just hiding the problem. One wa= y > > > is to change DISPC SIDLEMODE or MIDLEMODE to disallow idle/standby. T= he > > > other is to use certain fifo threshold values, which just seem to wor= k > > > for unknown reasons. > > >=20 > > > Considering that we already have a SIDLEMODE hack in DSS for omap3 wh= en > > > using DSI, I wonder if the omap3 PM + DSS combination is just plain > > > broken, and we should disallow idle. I'm not quite sure what are the > > > implications of that. > > >=20 > > > I'd appreciate comments from the PM people =3D). > >=20 > > This may be caused by one of the DPLLs going into autoidle. This can= =20 > > involve a significant wakeup latency. I'd suggest looking at DPLL3, wh= ich=20 > > provides the DSS interface clock, and DPLL4, which can provide the DSS= =20 > > functional clock. > >=20 > > Could you try: > >=20 > > 1. applying something like the patch at the bottom of this message and= =20 > > seeing if it makes any difference? > >=20 > > 2. if #1 does not work, changing the "dpll3" in the patch to "dpll4" ? > >=20 > > 3. if #2 does not work, disabling autoidle on both dpll3 and dpll4? >=20 > Disabling DPLL3 autoidle fixes the problem. Disabling DPLL4 autoidle > doesn't affect the problem. JFYI, I also tested changing DISPC's SYSCONFIG:CLOCKACTIVITY, which, to me, sounds a bit related to dpll autoidle. By default it's 0, "interface and functional clocks can be switched off". I tested the three other values, but none of them had any effect. Tomi --=-urjRnN/zoRZaA6wX7K4A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAABAgAGBQJPs3FBAAoJEPo9qoy8lh71stoP/jrvN2yGX8CdnR/vTiWEg1zX fVEPRB/OFreUVOrjjH2wwwERJ3k9Vtb1Z8ljzmtEFb0D3MXcSffFOP4f6me6PJCC IJ4LSN1ELzl6RX8emeCp3i04ll4mDqMo/OhPbF/r15sNmuwqvR6f9/7p3VNHjoER TCLSW3sIvIlchMF/gyYXSrkEIgjGMdSFLduIaREIXlCXAw2n/GzyQPMB7UxBS3cb jHLUiLO1sRiW+zbg3tlZqmwJI/rQPvOeyyN7ZVqNX9PR8NCRMJFGbZDJ2dsDN2Ua OSLjv7PueeLSMqg4o4l1TLrYLjLK6j5dzt7UjQoKi9looWc1inlrNA9Hr8C4QuJv uHAGPeCfRmLW0AHg168DarwaTpDE145ItcxoUbBwTgh3Zdh6ik/xtCw1TBBbOgU9 LkNeW2hEvn5tOJJdxPhUhVdt/X7pXHWtPW33my+kym/W3YskwCIcbpXAwBG/lSLa aKiqKIjmQyp8UXURDlErxz9rJj6Ql74XTeYXfA7ILLsyqTizM6rYy7KPekgCGclj tJkenX9adZGqx7Ez7T44CzjTzt8zoKzGBRDG/Hpp3IErYWXb3ZCR7NsSDp19Y02c Qb1aoz4TxLSXZ9vr4lD1XAafaSdk44VIAF5zh5qW7eOzGjKFgT5WMdZ23VlnWEKm 8LcLi431cNW6wU7/PbR2 =NO8v -----END PGP SIGNATURE----- --=-urjRnN/zoRZaA6wX7K4A--