From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: EHCI and MUSB do not discover devices without CONFIG_PM Date: Tue, 28 Nov 2017 06:39:13 -0800 Message-ID: <20171128143913.GS28152@atomide.com> References: <20171127220833.GA10070@lenoch> <20171128073328.GF10757@kroah.com> <20171128085751.GA28256@lenoch> <20171128093054.GA20720@kroah.com> <20171128093948.GA21766@lenoch> <20171128141131.GR28152@atomide.com> <20171128142851.GA12849@lenoch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20171128142851.GA12849@lenoch> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ladislav Michl Cc: Greg KH , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-omap@vger.kernel.org * Ladislav Michl [171128 14:31]: > On Tue, Nov 28, 2017 at 06:11:31AM -0800, Tony Lindgren wrote: > > * Ladislav Michl [171128 09:42]: > > > On Tue, Nov 28, 2017 at 10:30:54AM +0100, Greg KH wrote: > > > > bit-banging an ir decoder, ugh, you are in for a world of hurt. Can't > > > > you put a chip on the device that does this for you in hardware? > > > > > > OMAP has DM timer which can be externally trigered on edge. Perfect for > > > that purpose. But I cannot pinmux its input as hw designers did poor job. > > > And there are thousands of devices deployed. > > > > > > So it is about a lot of soldering or providing software solution. > > > > > > > Anyway, good luck! > > > > > > A little pointer would increase "luck" by several order of magnitudes. > > > > Hmm did you already try limiting cpuidle to C1 only in /sys? > > I have CONFIG_CPU_IDLE=n, which should be the same. Is that right? You will then use the omap3_pm_idle() that does not know much anything about latencies. > > From what I recall you just set the latency to less than C2 > > has. The cpuidle latencies are in struct omap3_idle_statedata > > omap3_idle_data[]. > > I disabled cpuidle and frequency scaling completely. The only thing that > make jitter difference is CONFIG_PM (see original thread). Right as then omap3_pm_idle() is disabled and only WFI is done :) Limiting things to C1 with cpuidle is probably what you need for having USB also working. > There's lot of pm_wkup interrupts with CONFIG_PM - order of magnitude > more than gp_timer. Hmm yeah that is true. And idling and waking up devices also takes some time. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html