From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tero Kristo Subject: Re: [PATCHv3 8/9] ARM: OMAP3: prevent per_clkdm from attempting manual domain transitions Date: Fri, 1 Jun 2012 11:06:47 +0300 Message-ID: <1338538008.8834.175.camel@sokoban> References: <1338470942-20185-1-git-send-email-t-kristo@ti.com> <1338470942-20185-9-git-send-email-t-kristo@ti.com> <4FC8016C.9000801@ti.com> Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:47971 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756214Ab2FAIGz (ORCPT ); Fri, 1 Jun 2012 04:06:55 -0400 In-Reply-To: <4FC8016C.9000801@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Jon Hunter Cc: linux-omap@vger.kernel.org, khilman@ti.com, paul@pwsan.com, linux-arm-kernel@lists.infradead.org On Thu, 2012-05-31 at 18:40 -0500, Jon Hunter wrote: > Hi Tero, > > On 05/31/2012 08:29 AM, Tero Kristo wrote: > > Previously, PER clock domain was always enabled, as the usecounts > > for this domain incorrectly always showed positive value. On HW > > level though, the domain enters idle as it is set in HW supervised > > mode. Now, when the usecounts reflect real values, PER domain will > > attempt to enter software supervised idle, which is not supported by the > > hardware/kernel that well, and causes multiple problems. First of all, > > coming back from idle, PER domain remains idle as the wakedeps have > > been disabled for the domain, and this causes a crash with the GPIO > > code, as the resume code attempts to access domain which is not active. > > Just enabling the interface clocks for the GPIO does not help, as they > > are autoidled and don't bring the domain out of idle. Secondly, there > > are multiple erratas for omap3, which say that the wakedeps should be > > enabled for the PER domain, see e.g. errata i582 for omap3630. > > > > Signed-off-by: Tero Kristo > > --- > > arch/arm/mach-omap2/clockdomains3xxx_data.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/arch/arm/mach-omap2/clockdomains3xxx_data.c b/arch/arm/mach-omap2/clockdomains3xxx_data.c > > index 6038adb..0dae4c8 100644 > > --- a/arch/arm/mach-omap2/clockdomains3xxx_data.c > > +++ b/arch/arm/mach-omap2/clockdomains3xxx_data.c > > @@ -282,7 +282,7 @@ static struct clockdomain usbhost_clkdm = { > > static struct clockdomain per_clkdm = { > > .name = "per_clkdm", > > .pwrdm = { .name = "per_pwrdm" }, > > - .flags = CLKDM_CAN_HWSUP_SWSUP, > > + .flags = CLKDM_CAN_HWSUP_SWSUP | CLKDM_SKIP_MANUAL_TRANS, > > .dep_bit = OMAP3430_EN_PER_SHIFT, > > .wkdep_srcs = per_wkdeps, > > .sleepdep_srcs = per_sleepdeps, > > So this change is just preventing software from clearing the wakeup-deps > and keeping the PER clock domain always in HW_AUTO? Basically yes. > Sorry for the dumb question, but what is the circumstance under which we > want to clear the wakeup-deps when we disable the clock domain? I am > just curious why this is being done in the first place. Not sure, maybe Paul can answer that question. Personally I don't see much point in fiddling with the wakedeps. -Tero