From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: DSS2/PM on 3.2 broken? Date: Wed, 18 Jan 2012 09:13:59 +0200 Message-ID: <1326870839.1954.23.camel@deskari> References: <20120110080849.5a242adf@notabene.brown> <20120112095940.0a54413e@notabene.brown> <20120113222045.37f9b4ec@notabene.brown> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-4MxNCEe5wbxksWRKisZg" Return-path: Received: from na3sys009aog107.obsmtp.com ([74.125.149.197]:54838 "EHLO na3sys009aog107.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753852Ab2ARHOH (ORCPT ); Wed, 18 Jan 2012 02:14:07 -0500 Received: by lahl5 with SMTP id l5so1830815lah.21 for ; Tue, 17 Jan 2012 23:14:03 -0800 (PST) In-Reply-To: <20120113222045.37f9b4ec@notabene.brown> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: NeilBrown Cc: Paul Walmsley , Joe Woodward , khilman@ti.com, t-kristo@ti.com, govindraj.r@ti.com, linux-omap@vger.kernel.org --=-4MxNCEe5wbxksWRKisZg Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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. I'm not sure if it is the case here, but DSS has restrictions about the 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. 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. Tomi --=-4MxNCEe5wbxksWRKisZg Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAABAgAGBQJPFnE3AAoJEPo9qoy8lh71ho0P/0ScC1UhhUBIFnCkuyqw8Pk5 xWrHxTKOjl9Xm9SHrfbe1S5Zf4QxLf9zwjG+IAQ0wiDD41MYA2kBJpCx5RsIbrxt N1zkf1c46r/C8GojMSkunYqe+iYrjXwiqrsvkH5/ExL/YNtJYL1K7iXOzaDQkGIu lGA1UqUVkTvcUdZD9Yq2/CpRG4Xu5xAhJX6rRaUm6hh8XXhQbdceGdv6pU69uvid iZuN0ce/VHZh3A/Za6aqrmuIr77idqG3PD4+FUNUkXWnjNngucXGYwN14YKMdK/w WcXvhfJC+JnxrwkOiJGunu/8defdOf1VpzI3+2jIHLF1litPK5OU1neEM/HnJ+nk rIfC2KZwG7njUPVFkEChmcfB5SPIv3zgB3oVSz28K+5jeTfvekwxcIbQrLVgcoIS 68DAInpzg0tnpUHCd4dtnZtAAsqkXcwwsLGehVYAFfykV9LtVr5AhjgLI/giPkAz QpWqHzlLqkW6OEMunTYMivpesyUTktGwE6kYGm9Js+MiW8DTSBvvyF5CCe01mYK/ iuHee7e/KE5YLPF7UKbe/LuUZR2OMChYTrYlp2yEDmgHDVPbVMCjdE6RKh2AWi6A Kv6ApcJnF0oMEvjg8Hsp7lsAlYBKEigQePjT4XJvkB2mqlBi2kv4t17sF78nUPFF usNzVyKwJ3oKjXsDYbmr =uxbL -----END PGP SIGNATURE----- --=-4MxNCEe5wbxksWRKisZg--