On Friday 05 April 2013 02:37 PM, Santosh Shilimkar wrote: > 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. > While pulling your 'for_3.10/fixes/pm' branch on top of Tony's pull request[1] sent to arm-soc already. In my tree, I had pulled Tony's couple of pull requests. Regards, Santosh [1] http://www.spinics.net/lists/arm-kernel/msg235788.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
