On Thursday 04 April 2013 11:12 PM, Kevin Hilman wrote: > Santosh Shilimkar <santosh.shilimkar@xxxxxx> writes: > >> On Thursday 04 April 2013 02:24 AM, Kevin Hilman wrote: >>> Santosh Shilimkar <santosh.shilimkar@xxxxxx> writes: >>> >>>> While waking up CPU from off state using clock domain force wakeup, restore >>>> the CPU power state to ON state before putting CPU clock domain under >>>> hardware control. Otherwise CPU wakeup might fail. The change is recommended >>>> for all OMAP4+ devices though the PRCM weakness was observed on OMAP5 >>>> devices first. >>> >>> Sounds reasonable, but can you describe the "weakness" a little more? >>> >>> IOW, what exactly happens if this is not done? It sounds like the CPU >>> might immediately go back to retention, but how does that happen unless >>> it does a WFI? >>> >> Its more of lock-up inside the hardware state machine and results >> are UN-predictable. We have seen hard-locks most of the time where system >> is just frozen. The hardware gets into wrong state machine if the power >> domain state isn't restored. I will add this information to changelog. >> >>> Also, this sounds like a fix to me, and should probably be broken out >>> accordingly. >>> >> Yeah. You mean a separate patch from the series, right ? This patch >> actually can be independently added. >> >> In case you decide to apply it for the fixes branch, updated patch >> at end of the email. > > Curious which branch you applied it to? It didn't apply cleanly to > v3.9-rc5 (but did with fuzz). > Mostly applied on top of the Tony's pull request branches. > So I've now added it to my for_3.10/fixes/pm branch. > Thanks. I will pull that in to re-base other patches. Regards, Santosh -- 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
