Hi Kevin, On 05/07/2012 12:15 PM, Kevin Hilman wrote: > Jon Hunter <jon-hunter@xxxxxx> writes: > >> Hi Will, >> >> On 04/26/2012 01:07 PM, Will Deacon wrote: >>> On Wed, Apr 04, 2012 at 12:15:24PM +0100, Will Deacon wrote: >>>> On Wed, Apr 04, 2012 at 12:29:49AM +0100, Paul Walmsley wrote: >>>>> >>>>> Part of the problem is that the clockdomain data for the emu_sys >>>>> clockdomain is wrong. Here's something to try to fix it. It might just >>>>> be enough to get it to work. >>>> >>>> Hmm, doesn't seem to work but I do see the following in dmesg when I try to >>>> use perf: >>>> >>>> powerdomain: waited too long for powerdomain emu_pwrdm to complete transition >>>> >>>> which is new with your patch. >>> >>> Sorry to nag, but does anybody have a clue where to go from here? I can >>> start digging in the OMAP PM code, but it's all new territory for me. >> >> I did a little playing around with this today and I think that I have figured out why this was not working (see below). Please can you try the following patch? I tried this on top of your series for perf/omap4. >> >> Paul, FYI. If this works for Will then I can re-base on top of the latest linux-omap and submit to the mailing list. >> >> Also, the above error about the emu_pwrdm is odd too. I noticed that the emu_pwrdm is always in the transitioning state. And when I say always, I mean that even if I check the power domain state while u-boot is running it is in the transitioning state. So even before the kernel starts. >> >> Cheers >> Jon >> >> From 9137ff9c1b382232de7443db0b51b7555846fb62 Mon Sep 17 00:00:00 2001 >> From: Jon Hunter <jon-hunter@xxxxxx> >> Date: Fri, 4 May 2012 16:48:45 -0500 >> Subject: [PATCH] ARM: OMAP4: Disable auto enable for EMU CLKDM >> >> The flag CLKDM_CAN_HWSUP allows the clock-domain to automatically transition >> to the enabled and disabled state. This means that as soon as we force a >> software wake-up on the clock domain, the clock domain will be allowed to idle >> and put back into the hardware auto state. For the EMU clock domain this is not >> what we want. We want to keep the clock domain in the software wakeup state >> while the clock domain is being used and put it back in to the hardware auto >> state when we have finished using the clock domain. >> >> Signed-off-by: Jon Hunter <jon-hunter@xxxxxx> > > With this patch, how is the clkdm ever idled? It does not! Sorry, I was so engrossed with figuring out why the EMU clkdm was being idled as soon as it was enabled, I forgot to check if is ever disabled once we terminated perf :-( > IIUC, your patch will get PMU interrupts working, but similarily to > previous patches in this thread, it works because it *never* allows the > EMU clkdm to idle. This is not a mergeable solution because it will not > allow CORE retention (and thus full-chip retention.) Right! > What we need is a solution that allows the clkdm to idle, and then to be > reinitialzed when it wakes up. Due to the way (I understand) resets in > the debugss, allowing the clkdm to idle will cause a reset, so the > PMU/CTI interrupts need to be reinitialzied after wakeup. Yes exactly I see that now. I have prototyped the 3 patches and this is working AND the EMU clkdm does go back to idle. I can send out to the list for review. > Kevin > > P.S. Please note there is also already a different fix in mainline for > the EMU clkdm data from Paul which adds the force wakeup flag and > removes the DISABLE_AUTO flag[1] (but leaves the ENABLE_AUTO flag, > because the hardware is capable.) Hmmm ... yes saw this, and you will have to excuse me as I don't fully follow the logic here. In fact, I am thinking we want the opposite ;-) >From looking, into this it seems to me that when PMU is running we want the EMU clock domain in software-wakeup state and when PMU is not running we want in the hardware auto state. By keeping the ENABLE_AUTO flag set, as soon as we enable the clock domain it is put right back into the HW_AUTO state and hence PMU is not working (see _enable() function in arch/arm/mach-omap2/omap_hwmod.c) So really what I think we want is to remove the ENABLE_AUTO flag to keep the clock domain in software wake-up and use the DISABLE_AUTO flag to put the clock domain back in HW_AUTO (note this requires a patch to perform this 2nd part). Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
