Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Going in circles without a real-time clock

rachelbythebay.com

Post reply on HN
Print view View original

141–150 of 157 posts

Re: Going in circles without a real-time clock

#141

Post by tdeck »

gorkish wrote: post #128

The Pi ecosystem is coming apart at the seams. Talk about falling off a pedestal. By the time you buy everything you need to make a Pi 5 even remotely usable and reliable today, you'll have spent as much as a small form factor PC. What do you need? 1. Special power supply - Yes, it's USB-C but it requires a high amperage 5V supply instead of accepting a higher voltage like most USB-C stuff 2. Active cooler - Pi 5 thr…

The raspberry pi is still a great and easy way to control GPIO lines. IMO that's it's strength, it was never a particularly capable desktop computer or server for any kind of load. The raspberry pi was underpowered compared to a "real computer" when it came out and that's still fine for many applications.

Re: Going in circles without a real-time clock

#142

Post by psz »

fuzzfactor wrote: post #136
dclowd9901 wrote: post #125

I’m not sure this is related or not but if there’s one thing I’ve learned about complex objects (engines, computers, software, sewing machines, etc), it’s that every _custom_ thing you do to it has some kind of order of magnitude impact on the overall complexity of the machine, and thus, you should avoid customizing it. At least if your primary concern is usability vs solving specific problems. It’s definitely served…

There is not much of an allowance any more for devices that are not on the internet 24/7 without fail. Multi-booting PCs with Windows and Linux over the years, I have seen the time sync problem go from nonexistent to show-stopper. For devices that you only need to connect to the internet occasionally or sporadically (so that's what you do), that's where I noticed it most. Linux sets the RTC to UTC, then when you rebo…

Set Linux to interpret RTC as local time, or set Windows to interpret RTC as UTC (possibly better, as it won't adjust to DST). https://askubuntu.com/a/1377011

Re: Going in circles without a real-time clock

#143

Post by eternityforest »

gorkish wrote: post #128

The Pi ecosystem is coming apart at the seams. Talk about falling off a pedestal. By the time you buy everything you need to make a Pi 5 even remotely usable and reliable today, you'll have spent as much as a small form factor PC. What do you need? 1. Special power supply - Yes, it's USB-C but it requires a high amperage 5V supply instead of accepting a higher voltage like most USB-C stuff 2. Active cooler - Pi 5 thr…

They seem to be obsessed with desktops, and ultra high performance homelab NASes.

They could have just use any old less powerful chip, like, whatever has at least 3B performance is fine, and used the money saved for stuff we actually need.

Maybe ditch those awful micro HDMIs, it's kind of a nasty connector and USB C exists.

Onboard lithium charging is a few cents. Better yet, onboard LTO charging, but it seems nobody does that yet. Why just stop at an RTC battery when you could have a few minutes of real backup power to help stop SD corruption?

While you're at it, add an onboard I2C FRAM or battery backed SRAM.

Instead of NVMe why not hire a few devs to go around fixing stuff that can't run well from the SD card?

Re: Going in circles without a real-time clock

#144

Post by cjbillington »

hcfman wrote: post #40
cjbillington wrote: post #28

The wireguard problem is a pain in the neck. Even if you're happy for your system to not have a realtime clock, when it does come online you'd want wireguard to not start until after the clock has synced to a timeserver. The below is what I'm doing at the moment, but I can't say I'm sure it's working - haven't seen wireguard start before the time is synced since doing it, but it could be probabilistic: systemctl enab…

Well... I see where you are going with this but is it necessary? What happens if the clock gets it's correct time sync back, will not wireguard come back online by itself ? Then the real solution might involve ensuring good clock sync. Using a GPS synched time source is good for this, such as this one :) https://github.com/hcfman/sbts-aru

No, I can't say I understand it fully - but if the clock goes backwards, peers will not talk to a client again until I restart the other peers' wireguard services. No matter if the client's clock is subsequently correct.

For some people, all their network access goes over wireguard and that includes time syncing. That's not the case for me, but for those people if wireguard isn't working their clock can't sync.

That GPS receiver looks cool! However an RTC and a battery will do just fine for me, which is the plan.

Re: Going in circles without a real-time clock

#145

Post by beryilma »

gorkish wrote: post #128

The Pi ecosystem is coming apart at the seams. Talk about falling off a pedestal. By the time you buy everything you need to make a Pi 5 even remotely usable and reliable today, you'll have spent as much as a small form factor PC. What do you need? 1. Special power supply - Yes, it's USB-C but it requires a high amperage 5V supply instead of accepting a higher voltage like most USB-C stuff 2. Active cooler - Pi 5 thr…

I have been happily using my Raspberry Pi 400 as my main home computer for years.

The tooling for light software development and hobby embedded hardware development has been great so far.

Re: Going in circles without a real-time clock

#146

Post by pbnjeh »

Dylan16807 wrote: post #138
gorkish wrote: post #128

The Pi ecosystem is coming apart at the seams. Talk about falling off a pedestal. By the time you buy everything you need to make a Pi 5 even remotely usable and reliable today, you'll have spent as much as a small form factor PC. What do you need? 1. Special power supply - Yes, it's USB-C but it requires a high amperage 5V supply instead of accepting a higher voltage like most USB-C stuff 2. Active cooler - Pi 5 thr…

The power supply is becoming less special over time. My first result for "usb c power supply" on amazon is a $25 anker 317 that supports PPS and will do 5 amps at any voltage. Not that that's an amazing price, but the feature is spreading. But I agree that the price to get a happy Pi is pretty harsh compared to a tiny PC.

I don't have Pi 5 to check this, but from what I've read, it does not support PPS. And such support is required; otherwise, even with a source that supports PPS, the connection will behave in a non-PPS fashion.

Apparently, cable quality is also demonstrating itself to be a significant factor in the Pi 5 power supply environment.

Regarding both these points:

https://github.com/raspberrypi/rpi-eeprom/issues/497

Re: Going in circles without a real-time clock

#147

Post by Dylan16807 »

pbnjeh wrote: post #146
Dylan16807 wrote: post #138

Earlier quoted context omitted.

The power supply is becoming less special over time. My first result for "usb c power supply" on amazon is a $25 anker 317 that supports PPS and will do 5 amps at any voltage. Not that that's an amazing price, but the feature is spreading. But I agree that the price to get a happy Pi is pretty harsh compared to a tiny PC.

I don't have Pi 5 to check this, but from what I've read, it does not support PPS. And such support is required; otherwise, even with a source that supports PPS, the connection will behave in a non-PPS fashion. Apparently, cable quality is also demonstrating itself to be a significant factor in the Pi 5 power supply environment. Regarding both these points: https://github.com/raspberrypi/rpi-eeprom/issues/497

What??

Then how the hell does it negotiate the power and know if it's attached to 3A or 5A?

Re: Going in circles without a real-time clock

#148

Post by gorkish »

Dylan16807 wrote: post #147
pbnjeh wrote: post #146

Earlier quoted context omitted.

I don't have Pi 5 to check this, but from what I've read, it does not support PPS. And such support is required; otherwise, even with a source that supports PPS, the connection will behave in a non-PPS fashion. Apparently, cable quality is also demonstrating itself to be a significant factor in the Pi 5 power supply environment. Regarding both these points: https://github.com/raspberrypi/rpi-eeprom/issues/497

What?? Then how the hell does it negotiate the power and know if it's attached to 3A or 5A?

Well, as it turns out, although a lot of stuff out there implies that the Pi uses USB-PD, it actually doesn't negotiate anything; it's just a dumb 5V peripheral. It can measure its own power (current/voltage) and has a current limit setting that the PMC will use to adjust clocks, etc. and alert on overcurrent conditions. If you hook up a higher amperage supply you have to change your boot config to the higher current limit. Everything is on you to make it work its weird not-quite-standards-compliant way.

The "Official Pi 5 USB-C Power Supply" is USB-PD compliant and as it is advertised as such in conjunction with the Pi5, I think that is where the confusion originates

Re: Going in circles without a real-time clock

#149

Post by Dylan16807 »

gorkish wrote: post #148
Dylan16807 wrote: post #147

Earlier quoted context omitted.

What?? Then how the hell does it negotiate the power and know if it's attached to 3A or 5A?

Well, as it turns out, although a lot of stuff out there implies that the Pi uses USB-PD, it actually doesn't negotiate anything; it's just a dumb 5V peripheral. It can measure its own power (current/voltage) and has a current limit setting that the PMC will use to adjust clocks, etc. and alert on overcurrent conditions. If you hook up a higher amperage supply you have to change your boot config to the higher current…

I thought the boot config was just an override.

The things I've been searching in the last few minutes suggest that the Pi can negotiate 5A but only if the power supply explicitly offers it as a PDO, which almost nothing does.

But even if that's right, it's almost as bad as not doing PD at all.

Edit: The documentation states "If the Raspberry Pi 5 firmware detects a supported 5A-capable supply, it increases the USB current limit for peripherals to 1.6A, providing 5W of extra power for downstream USB devices, and 5W of extra onboard power budget."

It also confirms no PPS, but it's not entirely dumb.

Re: Going in circles without a real-time clock

#150

Post by gorkish »

Dylan16807 wrote: post #149
gorkish wrote: post #148

Earlier quoted context omitted.

Well, as it turns out, although a lot of stuff out there implies that the Pi uses USB-PD, it actually doesn't negotiate anything; it's just a dumb 5V peripheral. It can measure its own power (current/voltage) and has a current limit setting that the PMC will use to adjust clocks, etc. and alert on overcurrent conditions. If you hook up a higher amperage supply you have to change your boot config to the higher current…

I thought the boot config was just an override. The things I've been searching in the last few minutes suggest that the Pi can negotiate 5A but only if the power supply explicitly offers it as a PDO, which almost nothing does. But even if that's right, it's almost as bad as not doing PD at all. Edit: The documentation states "If the Raspberry Pi 5 firmware detects a supported 5A-capable supply, it increases the USB c…

That may indeed be correct at least in some circumstances; maybe it at least works with some capability of the offical supply. In my experience I have had to use usb_max_current_enable=1 and PSU_MAX_CURRENT=5000 to get it to shut up and work.

Here's the thing though; the simple fact that we have to even have this discussion because the Rpi5 continues to be super damn weird is enough evidence for me that the platform has jumped the shark. I don't know whether to blame Broadcom or the Pi Foundation, but the Pi 5 suuuuuucks. Man, I wanted to love it though; it's the only board I have even been been able to buy from them in the last FOUR YEARS

Post reply on HN