On Friday 12 July 2013 06:10 AM, Suman Anna wrote: > On 07/11/2013 04:59 AM, Grygorii Strashko wrote: >> Hi, >> >> On 07/11/2013 09:32 AM, Tony Lindgren wrote: >>> * Felipe Balbi <balbi@xxxxxx> [130710 09:18]: >>>> >>>> On Wed, Jul 10, 2013 at 07:07:04PM +0300, Felipe Balbi wrote: >>>>> how about something like below ? It makes omap_device/hwmod and >>>>> pm_runtime agree on the initial state of the device and will prevent >>>>> ->runtime_resume() from being called on first pm_runtime_get*() done >>>>> during probe. >>>>> >>>>> This is similar to what PCI bus does (if you look at pci_pm_init()). >>>>> >>>>> commit 59108a500b4ab4b1a5102648a3360276dbf7df6f >>>>> Author: Felipe Balbi <balbi@xxxxxx> >>>>> Date: Wed Jul 10 18:50:16 2013 +0300 >>>>> >>>>> arm: omap2plus: unidle devices which are about to probe >>>>> >>>>> in order to make HWMOD and pm_runtime agree on the >>>>> initial state of the device, we will unidle the device >>>>> and call pm_runtime_set_active() to tell pm_runtime >>>>> that the device is really active. >> Don't think that it's good idea ( >> I've checked some driver's and think this patch will enable some devices >> unpredictably: >> - hwspinlock >> - mailbox >> - iommu >> - ipu >> All above devices need to be enabled on demand only (no >> pm_runtime_get*() calls in probe). More over, some of them have very >> specific enabling sequence - like ipu). >> >> May be Summan can say more on that. > > Indeed, this is a problem for any of the slave processor devices. > mailbox and iommu would be slaves to the remoteproc and the drivers have > a specific sequence of bringing up a processor. The current > hwmod/omap_device code is such that these devices will be left in reset > and the driver code use the omap_device_(de)assert_hardreset API > together with omap_device_enable code to bring up the devices. The > remoteproc driver also needs to assert the resets (there are other > problems associated with using omap_device_idle for remoteproc and > iommu) for bringing up the devices after a suspend sequence. hwspinlock > and mailbox may get away since they are in CORE domain, but definitely > an issue for iommu and remoteproc. I would think that this would also > affect other compute devices like IVAHD, ISS, SGX. Today, for these IPs I guess hwmod waits for the resets to be de-asserted, right? /* * If an IP block contains HW reset lines and all of them are * asserted, we let integration code associated with that * block handle the enable. We've received very little * information on what those driver authors need, and until * detailed information is provided and the driver code is * posted to the public lists, this is probably the best we * can do. */ if (_are_all_hardreset_lines_asserted(oh)) return 0; What if this information is send back to omap_device() through a return value so omap_device() knows about this too, so it avoids marking the omap device as enabled? Wouldn't that fix the issue? > > regards > Suman > >> >>>>> >>>>> By the time driver's probe() is reached, a call to >>>>> pm_runtime_get_sync() will not cause driver's >>>>> ->runtime_resume() method to be called at first, only >>>>> after a successful ->runtime_suspend(). >>>>> >>>>> Signed-off-by: Felipe Balbi <balbi@xxxxxx> >>>> >>>> btw, this is RFC, haven't tested at all. >>> >>> Yes it does not compile, then removing the extra ; at the end >>> of the functions, it oopses with a NULL pointer exception. >>> >>> Regards, >>> >>> Tony >>> -- >>> 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 >>> >> > -- 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