Ticket #10899 (closed defect: fixed)

Opened 3 years ago

Last modified 3 years ago

XO 1.75 dual RTC synchronization

Reported by: pgf Owned by: buytenh
Priority: normal Milestone: 1.75-software
Component: kernel Version: 1.75-A2
Keywords: Cc: saadia, cjb, pgf
Action Needed: design Verified: no
Deployments affected: Blocked By:
Blocking:

Description

<smithbone> does the rtc driver work now?
<pgf> it's complicated.
<pgf> yes and no.
<cjb> smithbone: it works but it doesn't do what you think it does :-)
<pgf> there are two rtcs.
<pgf> one in the chip, and one not in the chip.
<wad> Damn Marvell
<pgf> the one inside isn't powered when the chip is off.
<pgf> so we have one outside that is.
<pgf> but the one outside doesn't have alarms.
<pgf> so if we want alarms, we have to use the one inside, while the system is running.
<pgf> so we have to sync the inner clock to the outer clock, at boot, and vice-versa on shutdown.

we'll have to explore how linux manages two RTC drivers.

Attachments

screenlog-snipped.log (138.3 kB) - added by martin.langhoff 3 years ago.

Change History

Changed 3 years ago by Quozl

  • owner set to buytenh
  • next_action changed from never set to design
  • component changed from not assigned to kernel
  • milestone changed from Not Triaged to 1.75-software

Triage. 1.75-software and 1.75-firmware.

Changed 3 years ago by martin.langhoff

Changed 3 years ago by martin.langhoff

  • cc cjb added

Changed 3 years ago by martin.langhoff

apologies - wrong bug

Changed 3 years ago by Quozl

#10827 related.

Changed 3 years ago by Quozl

#11400 related.

Changed 3 years ago by saadia

  • cc pgf added
  • status changed from new to closed
  • resolution set to fixed

The clock will not be synchronized. The external clock (idt1338) will be used for syncing time at startup and reboot by setting CONFIG_RTC_HCTOSYS_DEVICE to /dev/rtc1. During operation, /dev/rtc will be linked to /dev/rtc1 for hwclock's benefit. The internal SOC real time clock will be used for alarms, and will keep the time since boot.

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