Raspberry Pi 4 can finally boot directly from USB • Hacker News Board

Re: Raspberry Pi 4 can finally boot directly from USB

#221

Post by simongr3dal » Sat, Sep 19, 2020, 3:27 PM UTC

snvzz wrote: post #212

Rpi4 and still no usb version of bootloader. What am I missing? # rpi-eeprom-update BCM2711 detected BOOTLOADER: up-to-date CURRENT: Tue 10 Sep 2019 10:41:50 UTC (1568112110) LATEST: Tue 10 Sep 2019 10:41:50 UTC (1568112110) VL805: up-to-date CURRENT: 000137ab LATEST: 000137ab I wish this was better documented.

You gotta do:

  $ sudo apt update
  $ sudo apt upgrade
  $ sudo apt dist-upgrade

Then do a restart and the bootloader should be updated, if that doesn't work you also need to do a:

  $ sudo rpi-update

Now the eeprom should be updated and the default option should be to boot from SD, then USB.

Re: Raspberry Pi 4 can finally boot directly from USB

#222

Post by javajosh » Sat, Sep 19, 2020, 3:34 PM UTC

salawat wrote: post #129

rektide wrote: post #71

Earlier quoted context omitted.

> It depends on what layer you care about. At the application layer it is completely open. I'm not down with this injection of skepticism. This is slipperly language trying to make a pretty clearly contrasted situation murky. Sure, if you just need something to process instructions, maybe the well-defined cpu architecture is enough. But kernels need things like timers to run. They need USB hosts to attach keyboards &…

I've heard some of Broadcom's stingeyness with documentation may stem from the risks created by the perverse environment created by IP laws. With a patent troll only one manual away, I can somewhat understand to a degree holding things close to your chest if you want to continue to exist. I mean it sucks massively, but I can at least understand it. It's part of why I strongly disagree with the "IP" side of semiconduc…

IANAL, but it would seem that the more documentation you release on your patented product the MORE you are protected, since it becomes less likely that they independently discovered your solution.

Re: Raspberry Pi 4 can finally boot directly from USB

#223

Post by stragies » Sat, Sep 19, 2020, 3:40 PM UTC

secondcoming wrote: post #87

systemvoltage wrote: post #32

Not a fan of Raspberry Pi. It hides behind proprietary Broadcom chip, no DSI/MIPI support and you're at the mercy of Raspberry PI for any sort of commercial implementation (RPi Zero and independent module). They do guarantee upto 2026 availability for their DIMM modules which is nice. We wanted to build commercial device using RPi but its a no go due to its blackbox nature. What they should do is to leverage their po…

Anything capable of playing HD content is going to have a binary blob. The Pi (at least the first version of it) used the same chipset that was in the Nokia N8. Even Nokia got given those blobs.

I also thought that, but then somebody here mentioned (in another topic), that the RK3388 from Rockchip runs entirely blobless. I'm having trouble digging up that post, but i'm sure I did not dream it. I'm hoping that statement applies to other members of the Rockchip family too.

Re: Raspberry Pi 4 can finally boot directly from USB

#224

Post by loxias » Sat, Sep 19, 2020, 4:34 PM UTC

Dylan16807 wrote: post #175

joshspankit wrote: post #144

Earlier quoted context omitted.

At most 10ms. Sub 1ms would be awesome. And yes, definitely. If you can build in a “chromecast receiver” so that a user could cast to multiple synced speakers (at full quality), you’d definitely have my attention

It's worth noting that for two speakers playing the same audio, a 5ms offset will move the point of perfect sync by less than a meter. Going below a millisecond is definitely overkill territory.

I beg to differ: a good rule of thumb is that an (audio) sample takes about 8mm (44.1k). By the time you're a full 1ms late, that's a 44 sample difference between the two (or that's as though the speakers were about a third a meter apart.

And that distance, you're gonna hear some uncomfortable comb filtering. A third of a meter corresponds to a frequency of about 1khz, which is right smack dab in the middle of a critical band, so you WILL hear the constructive and destructive interference around ~1khz.

(and _5ms_? That means the speakers are now ~220 samples out of sync, so I'd expect any lows around 200hz to have some destructive interference, making the music sound hollow.)

1ms of sync is FAR less than adequate. It took effort, but I was able to get a distributed set of raspis to within about 5 samples at 44.1k, and I think I can do better.

Why do I know this or care? :) I've done (and still do) a lot of research (and inventions) in the field of microphone array processing and audio source localization -- tracking objects purely by their sound. With cheap commodity equipment I can generally get a resolution of 5cm, and with lots of fine tuning I was able to do sub-cm tracking.

Re: Raspberry Pi 4 can finally boot directly from USB

#225

Post by MegaDeKay » Sat, Sep 19, 2020, 4:38 PM UTC

vinw wrote: post #171

blibble wrote: post #96

Earlier quoted context omitted.

I actually tried this and it turned out to be quite a bit more complicated than predicted, due to clocks on the pis being slightly different "I'll just sling udp multicast of the PCM samples around the network, can't be that hard right?" ended up using MPD with pulseaudio over TCP, and they get out of sync after a few minutes, but good enough

Take a look at snapcast if you want to fix your out-of-syncness https://github.com/badaix/snapcast

"Typically the deviation is below 0.2ms." Impressive!

Re: Raspberry Pi 4 can finally boot directly from USB

#226

Post by kingosticks » Sat, Sep 19, 2020, 4:38 PM UTC

m4rtink wrote: post #211

systemvoltage wrote: post #32

Not a fan of Raspberry Pi. It hides behind proprietary Broadcom chip, no DSI/MIPI support and you're at the mercy of Raspberry PI for any sort of commercial implementation (RPi Zero and independent module). They do guarantee upto 2026 availability for their DIMM modules which is nice. We wanted to build commercial device using RPi but its a no go due to its blackbox nature. What they should do is to leverage their po…

Not just all that, but also hardware DRM (!!) on the camera module interface: https://mobile.twitter.com/marcan42/status/10884725497159188...

And the rebuttal:

https://twitter.com/EbenUpton/status/1088440503622909952?s=2...

The outrage and entitlement in the original tweet is laughable. It's an education charity, they need to raise money to fund their cause and do their work. I'm glad they do stuff like this. I bought both versions of the camera.

Re: Raspberry Pi 4 can finally boot directly from USB

#227

Post by ukyrgf » Sat, Sep 19, 2020, 4:53 PM UTC

fredley wrote: post #179

LeoPanthera wrote: post #47

Earlier quoted context omitted.

Two play music, one into my hifi, one into my home audio distribution system. One is setup for RetroPie. One has LibreELEC installed, showing TV from my HDHomeRun. One has a GPS hat and is a local NTP server. And one boots into an Amiga emulator because I'm very old and nostalgic.

Surprised not to see Pi Hole on that list!

Any old SBC can run that reliably on it's own, the parent is talking about swapping out the OS with netboot on the fly.

Re: Raspberry Pi 4 can finally boot directly from USB

#228

Post by kingosticks » Sat, Sep 19, 2020, 4:54 PM UTC

snvzz wrote: post #212

Rpi4 and still no usb version of bootloader. What am I missing? # rpi-eeprom-update BCM2711 detected BOOTLOADER: up-to-date CURRENT: Tue 10 Sep 2019 10:41:50 UTC (1568112110) LATEST: Tue 10 Sep 2019 10:41:50 UTC (1568112110) VL805: up-to-date CURRENT: 000137ab LATEST: 000137ab I wish this was better documented.

There is a section of the documentation labelled 'Updating the bootloader' at https://www.raspberrypi.org/documentation/hardware/raspberry...

Re: Raspberry Pi 4 can finally boot directly from USB

#229

Post by LeoPanthera » Sat, Sep 19, 2020, 5:15 PM UTC

fredley wrote: post #179

LeoPanthera wrote: post #47

Earlier quoted context omitted.

Two play music, one into my hifi, one into my home audio distribution system. One is setup for RetroPie. One has LibreELEC installed, showing TV from my HDHomeRun. One has a GPS hat and is a local NTP server. And one boots into an Amiga emulator because I'm very old and nostalgic.

Surprised not to see Pi Hole on that list!

My router runs pfSense so I don't need Pi Hole, I can use pfBlockerNG instead, which is built in.

Re: Raspberry Pi 4 can finally boot directly from USB

#230

Post by loxias » Sat, Sep 19, 2020, 5:18 PM UTC

joshspankit wrote: post #106

blibble wrote: post #96

Earlier quoted context omitted.

I actually tried this and it turned out to be quite a bit more complicated than predicted, due to clocks on the pis being slightly different "I'll just sling udp multicast of the PCM samples around the network, can't be that hard right?" ended up using MPD with pulseaudio over TCP, and they get out of sync after a few minutes, but good enough

The different clocks is a real hurdle. I have to give credit to Apple on this one, as they had the genius idea to make the buffer >1s, and send control messages independent of the audio stream. There’s gotta be a way to do it with PTP and the same ideas but clearly it’s either an extremely difficult problem, too niche, or both.

Correct. You use PTP+NTP, the RT_PREEMPT patches, and then you have to deal with a constantly varying resampling ratio (!!) And not only that, but if you don't want nasty artifacts, the a LOT of thought also has to go into your filter design. It's hazy, but I remember using a pair of orthonormal time-varying allpass IIR QMF filters, with extra black magic I'm blanking on that allowed me to reduce the complexity of finding the coefficients for, and computing the filters by at least a factor of 4. Fun stuff. I think half the coefficients in the EQMF were zero, and of the other half, half were the reciprocal of another, which led to a fast implementation.

But yeah! I've done that. Kept audio streams to within a few samples of alignment for more than 24 hours. It was fun, and yes, somewhat hard. "will more than happily do it again for money". :)