Opened 4 years ago

Closed 3 years ago

#10899 closed defect (fixed)

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
Blocked By: Blocking:
Deployments affected: Action Needed: design
Verified: no

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 (1)

screenlog-snipped.log (138.3 KB) - added by martin.langhoff 4 years ago.

Download all attachments as: .zip

Change History (7)

comment:1 Changed 4 years ago by Quozl

  • Action Needed changed from never set to design
  • Component changed from not assigned to kernel
  • Milestone changed from Not Triaged to 1.75-software
  • Owner set to buytenh

Triage. 1.75-software and 1.75-firmware.

Changed 4 years ago by martin.langhoff

comment:2 Changed 4 years ago by martin.langhoff

  • Cc cjb added

comment:3 Changed 4 years ago by martin.langhoff

apologies - wrong bug

comment:4 Changed 3 years ago by Quozl

#10827 related.

comment:5 Changed 3 years ago by Quozl

#11400 related.

comment:6 Changed 3 years ago by saadia

  • Cc pgf added
  • Resolution set to fixed
  • Status changed from new to closed

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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