On Friday 30 March 2012 02:04 PM, Archit Taneja wrote: > On Friday 30 March 2012 02:01 PM, Santosh Shilimkar wrote: >> + Kevin >> >> On Friday 30 March 2012 01:56 PM, Tomi Valkeinen wrote: >>> On Fri, 2012-03-30 at 13:51 +0530, Shilimkar, Santosh wrote: >>>> On Fri, Mar 30, 2012 at 1:37 PM, Tomi >>>> Valkeinen<tomi.valkeinen@xxxxxx> wrote: >>> >>>>> All OMAP4 versions seem to be affected. I couldn't find a mention >>>>> about >>>>> this in the mainline kernel. Any ideas how and where this should be >>>>> fixed? >>>>> >>>> It's not patched for mainline. Generally clock-domain code >>>> is abstracted from drivers but considering the errata and affected >>>> modules, I guees it should be handled by DSS driver >>>> since that is where the state of DSS or ISS will be known. Note >>>> ISS will be automatically taken care since it will always use disaplay. >>>> >>>> In internal tree's this was handled as part of DSS early suspend/resume >>> >>> That version doesn't work as it uses functions that are not exported to >>> drivers. >>> >>> I don't know much about the clock domain code, but I hope there's a way >>> to handle it there. Otherwise I guess I need to add a new set of >>> platform callback functions, so that the dss driver can call >>> arch/arm/mach-omap2 code to enable and disable the work-around. I >>> dislike that because I'm currently trying to remove those kinds of hacks >>> to make dss work better with DT =). >>> >> I agree. In fact I faced similar issue when I briefly tried moving >> OMAP cpuidle code to drivers/idle/*. >> >> That time me and Kevin concluded that till we move the powerdomain, >> clockdomain code to drivers/* and export it, the cpuidle movement >> needs to be deferred. > > How about preventing the issue to occur by keeping DSS and ISS in > No-standby mode for the affected OMAP versions. The errata says: > > "Such a situation can occur when the impacted initiator is generating > short MStandby pulses (pulse durations less than one L4 clock cycle)" > > Chaning the mstandby hwmod data for DSS and ISS would prevent the need > for exporting these clock domain functions only for this errata. > That will just break PM :-) With this change DSS will never assert standby and then PRCM can never send idle-req to modules. Indirectly no power transitions. 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
