"Peter 'p2' De Schrijver" <peter.de-schrijver@xxxxxxxxx> writes: > On Fri, Nov 19, 2010 at 05:14:15PM +0100, ext Derrick, David wrote: >> >-----Original Message----- >> >From: Jean Pihet [mailto:jean.pihet@xxxxxxxxxxxxxx] >> >Sent: Friday, November 19, 2010 9:37 AM >> >> >On Thu, Nov 18, 2010 at 7:34 PM, Jean Pihet <jean.pihet@xxxxxxxxxxxxxx> >wrote: >> >> On Thu, Nov 18, 2010 at 7:27 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: >> >>> * Jean Pihet <jean.pihet@xxxxxxxxxxxxxx> [101118 10:06]: >> >>>> On Thu, Nov 18, 2010 at 6:52 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: >> >>>> >> >>>> About the DPLL lock: >> >>>> 1) wait_sdrc_ok is only called when back from the non-OFF modes, >> >>>> 2) I checked that when running wait_sdrc_ok the CORE is already out of >> >>>> idle and the DPLL is already locked. Note: l-o code has no support for >> >>>> the voltages OFF and the external clocks OFF. >> >>>> >> >>>> What to conclude from 1) and 2)? In my test setup ot looks like >> >>>> wait_sdrc_ok is of no use, but I agree this a premature conclusion. >> >>> >> >>> Yeah we should figure out in which cases wait_sdrc_ok is needed. >> >>> >> >>> BTW, are you sure you're hitting core idle in your tests? >> >> Yes it is OK from the console messages and the counters values in >> >> /debug/pm_debug/count. >> >> >> >> Let me confirm asap with the PRCM registers dump. >> >> >Here is what I experimented: >> >1) added a cache flush (v7_flush_kern_cache_all) just before WFI, in all >cases, >> >2) checked the real state entered in low power mode from the console >> >messages, the output of /debug/pm_debug/count and PRCM registers dump >> >> >2) is OK, which means that the RET and OFF modes are correctly hit. >> >> >Can I conclude from 1) that the wake-up code is not running from the >> >cache in RETention? >> >> [Derrick, David] >> >> To add some context to the wait_sdrc_ok function and why it was added: >> >> wait_sdrc_ok was added because the DLL takes 500 L3 clock cycles >> to lock. So you do not want to go back to DDR before DLL is locked. Also, we >> found some times DLL never locked so we introduced the DLL kick procedure to >> force it to lock. >> > > The root cause for the DLL not locking has been found though and a > workaround implemented. So it should work now :) Is the workaround for this reflected in Nishanth's series? Kevin > That still leaves the > 500 L3 cycle delay though. > > Cheers, > > Peter. -- 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
