On Friday 19 August 2011 17:07:52 Gordan Bobic wrote: > On Fri, 19 Aug 2011 16:26:37 +0200, Marc Dietrich <[email protected]> > > On Friday 19 August 2011 16:10:43 Gordan Bobic wrote: > >> On Fri, 19 Aug 2011 15:55:57 +0200, Marc Dietrich <[email protected]> > >> > Am Freitag 19 August 2011, 11:18:31 schrieb Gordan Bobic: [...] > >> Well, my plan was to up the timings in > >> arch/arm/mach-tegra/board-paz00-memory.c. Can you confirm whether > >> the values there are in units of clock cycles? Or is it ns? Also which > >> line corresponds to CAS? I can see RAS, RC, RCD, RRD, RFC, but can't see > >> a value for CAS, which is, at least in theory, the most imporant one. > > > > AFAIK, they are in cycles, but as I said, these values are not used > > now (see the ifdef 0 at the end of the file). The reason is that I don't > > have the values for 166 MHz on Micron and the Hynix tables caused > > instabilities. So they are just there as a "reminder". But of course, you > > can remove the ifdef and try yourself. > > Ah, OK. I missed that. Are the registers for setting the timings > write-only? If not, it should be possible to dump out the default > timings, should it not? They may not be correct, but it would at last > give a good starting value for adjusting.
you can have a dump of the bcd using the bcd_dump (from the cbootimage tool from chromos). These are the timings the bootloader programs. > As for timings at 166 MHz vs. 333 MHz, most RAM chips I have seen have > the spec sheet listing the timings in ns, so as the clock speed goes > down, the cycle timings proportionately decrease (fewer cycles to wait > at lower clock speed). So 166MHz timings _should_ be half the 333MHz > timings (rounding up). I don't know much about RAM and timings, so you may be right that they are based on ns. I havn't found any useful info from the chip datasheets regarding timings at different clock rates though. > >> > [...] > >> > It could also be related to power supply. What we do is modifing the > >> > voltage supplies for serveral power sources. I had the feeling, that > >> > Toshiba undervoltaged some CPU supplies in order to save energy (compared > >> > to other boards). So I increased SM1 from 1V to 1.2V which may have been > >> > wrong. > >> > >> How did you do this? > > > > check board-paz00-power.c > > Just looking now. Are you referring to the REGULATOR_INIT macro and > specifically the line that defines a struct with: > > REGULATOR_INIT(sm1, 725, 1200, true)? > > Are you saying that the default value as provided by Toshiba was > > REGULATOR_INIT(sm1, 725, 1000, true)? correct. Please understand that these values are just best guesses on what the Toshiba code does. In fact, kernel 2.6.38 has nothing to do with the original code base because it's a total rewrite. You may check arch/arm/mach- tegra/odm_kit/adaptations/pmu/tps6586x/nvodm_pmu_tps6586x.c for reference. > Have you experienced significant instability with it set to 1000mV? Or > was this change based on observation what other boards do? I'm wondering > if the 20% increase in voltage (44% increase in thermal load!) might > actually push things outside the thermal limits of cooling and thus be > responsible for contributing to the instability. No, neither produced problems here, but I haven't make the same stress tests as you. > >> > It would be nice if you could test a .32 based kernel and see if > >> > it also happens there. Also you could try your new model. > >> > >> I haven't tried 2.6.32 because I couldn't find one at the time, but > >> I tried the old 2.6.29 and 2.6.38, and the instability on my old > >> AC100 was the same. Haven't tried it on the new one yet. Do you think > >> 2.6.32 could be behaving differently to both of those? If so, why? Where > >> can I get the Tegra-patched 2.6.32 kernel? > > > > gitorious.org/ac100? (on the front page) > > I'll try it, but I'm curious to know why you think 2.6.32 might be > better in this sense than 2.6.29 and 2.6.38. ah, you tried 2.6.29. I think that's also ok, but 2.6.32 is a bit newer. They share most of the ac100 specific code, but there my be differences. Marc _______________________________________________ Mailing list: https://launchpad.net/~ac100 Post to : [email protected] Unsubscribe : https://launchpad.net/~ac100 More help : https://help.launchpad.net/ListHelp
