* Alexander Holler <holler@xxxxxxxxxxxxx> [110405 03:11]: > Hello, > > Am 04.04.2011 16:29, schrieb Alexander Holler: > > >it just happened here that the rechargeable backup battery for the RTC > >on a TPS65950 run out off power, because of some days while the device > >wasn't powered. > > > >Afterwards I couldn't read or set the clock with hwclock using a kernel > >2.6.37.n or 2.6.38.n. > > > >I don't have a fix, but I think I've analyzed the problem and can offer > >a (bad) workaround. > > > >What happens is the following: > > > >When trying to read or set the clock with hwclock, the driver (rtc-twl) > >starts an alarm, but the irq for the alarm will never get called. The > >result is that a select in hwclock times out (for both operations, read > >or set). > > > >Because I had this clock running before, I've got the idea to try one of > >those old OMAP-kernels (2.6.32-angstrom) using the same userland. > >And with that kernel I could set the clock. > >Using 2.6.37 or 2.6.38 afterwards, hwclock did function again, both read > >an set are working. > > > >So it looks like there is a catch22 in kernels >=2.6.37 (I haven't > >tested .33-.36): > > > >When the clock was never set, the alarm(-irq) doesn't work, so hwclock > >doesn't work, so one can't set the clock. > > It turns out that the missing/wrong initialization of the msecure > line is the problem which disabled setting the clock. After doing > that through a quick hack, I could set the clock. > > I'm using a BeagleBoard C4, but I can't find any msecure > initialization for other boards too. > > What happened with those patches? E.g. those: > > http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg16125.html Looks like these need reposting. Maybe worth doing generic omap RTC init code though? Tony -- 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
