PCI Express on the Raspberry Pi 4 • Hacker News Board

Re: PCI Express on the Raspberry Pi 4

#151

Post by justinclift » Wed, Jul 10, 2019, 10:45 PM UTC

buildbuildbuild wrote: post #100

beatgammit wrote: post #98

Earlier quoted context omitted.

I think you mean the RockPro64. The Rock64 only has 4 cores and no PCIe. That being said, I missed the PCIe on the specs last time I was comparing SOCs and I had forgotten about hackerboards, thanks for the reminder!

http://rockpi.org/ :)

Not seeing a mention of PCIe there on the board?

Re: PCI Express on the Raspberry Pi 4

#152

Post by justinclift » Wed, Jul 10, 2019, 10:45 PM UTC

buildbuildbuild wrote: post #72

Fun. If you want PCIe on a SBC without the soldering, I highly recommend perusing Hackerboards. I'm very happy with my RockPi 4 (4GB RAM, PCIe, USB 3, 6 cores), which I discovered through their excellent database. https://www.hackerboards.com/search_boarddb.php

Not seeing a mention of PCIe as an option that can be searched?

Re: PCI Express on the Raspberry Pi 4

#153

Post by noobermin » Thu, Jul 11, 2019, 2:36 AM UTC

anderspitman wrote: post #144

noobermin wrote: post #32

Now this is the content I come to HN for. A serious hack just days after the 4 was released. Kudos to the OP. I envy people like OP for their tenacity. I barely have time to follow what's happening in IT, much less get ahead of the pack in doing cools hacks like this.

I'm sure you are but just in case are you aware of hackaday.com?

Of course! HN is just a good digest of things on the maker side to the fairly abstract CS stuff to math and physics and all in between. It sure beats the political stuff that becomes tiresome (even though I succumb and engage in it like many posters here).

Re: PCI Express on the Raspberry Pi 4

#154

Post by vardump » Thu, Jul 11, 2019, 2:50 AM UTC

kejaed wrote: post #48

cesarb wrote: post #42

Earlier quoted context omitted.

> Wouldn't the gigabit LAN be a better fit for this? I might be showing my age but... Imagine a Beowulf cluster of these! (For those who don't know the reference, this used to be a common saying in slashdot back in the day.)

+5 Funny

Until metamoderator wrath.

To everyone who feels left out: old slashdot.org "humor".

Re: PCI Express on the Raspberry Pi 4

#155

Post by gtyras2mrs » Thu, Jul 11, 2019, 5:16 AM UTC

justinclift wrote: post #151

buildbuildbuild wrote: post #100

Earlier quoted context omitted.

http://rockpi.org/ :)

Not seeing a mention of PCIe there on the board?

Scroll down a bit. M.2 on the backside.

Listed under Storage in the specs.

Re: PCI Express on the Raspberry Pi 4

#156

Post by justinclift » Thu, Jul 11, 2019, 6:41 AM UTC

gtyras2mrs wrote: post #155

justinclift wrote: post #151

Earlier quoted context omitted.

Not seeing a mention of PCIe there on the board?

Scroll down a bit. M.2 on the backside. Listed under Storage in the specs.

Isn't M.2 storage specific?

eg not a useful PCIe slot for anything other than plugging in an SSD

Re: PCI Express on the Raspberry Pi 4

#157

Post by hipboi » Thu, Jul 11, 2019, 7:08 AM UTC

justinclift wrote: post #156

gtyras2mrs wrote: post #155

Earlier quoted context omitted.

Scroll down a bit. M.2 on the backside. Listed under Storage in the specs.

Isn't M.2 storage specific? eg not a useful PCIe slot for anything other than plugging in an SSD

M.2 has full four lanes PCIe, you can use M.2 to PCIe x4 adapter and use all the standard PCIe cards.

Re: PCI Express on the Raspberry Pi 4

#158

Post by Millennium » Thu, Jul 11, 2019, 11:30 AM UTC

kllrnohj wrote: post #130

Millennium wrote: post #101

If a Pi is capable of this already, why not replace the Ethernet, charging, micro-HDMI, and USB ports with a boatload of type-C Thunderbolt ports (plus support for the HDMI 1.4 alt mode)? Would 8xUSB-C cost that much more than 1xUSB-C+1xEthernet+2xMicro-HDMI+2xUSB3+2xUSB2 (with no PCI Express), in exchange for a considerably more flexible device?

Because there's no where remotely close to enough PCI-E lanes off of the SoC to do that. Thunderbolt 1/2 requires a pcie gen2 x4 connector to have enough bandwidth. The SoC in the pi4, the Broadcom BCM2711, has just a single gen2 pcie lane. 1/4th the required bandwidth for thunderbolt 1/2, and a mere 1/8th the requirement for thunderbolt 3. To get a full 8x thunderbolt 3 connectors you need a staggering 32 pcie gen3…

Welp, that explains it. I stand corrected. Thanks.

Re: PCI Express on the Raspberry Pi 4

#159

Post by planteen » Thu, Jul 11, 2019, 1:04 PM UTC

vardump wrote: post #129

qdot_me wrote: post #6

Earlier quoted context omitted.

Hack’s creator here - it’s on my list of things to try. GPUs are notoriously hard to get to work on non-intel, having tried to get a few up on Alpha and Itaniums in the past. VideoBIOS expects to run and expects a well behaving Intel CPU to do the power-up. That said X can sometimes emulate these quite well. On ARM we’d also run into alignment issues and likely other quirks - but in principle...

> On ARM we’d also run into alignment issues... Just don't use ARMv5 or older. ARMv6+ supports unaligned access.

At least on ARMv7, it's up to the MMU, not the CPU. I've worked with Cortex-A9s that trap the unaligned access. You can write a handler or crash.

Re: PCI Express on the Raspberry Pi 4

#160

Post by bjoli » Thu, Jul 11, 2019, 1:24 PM UTC

buildbuildbuild wrote: post #72

Fun. If you want PCIe on a SBC without the soldering, I highly recommend perusing Hackerboards. I'm very happy with my RockPi 4 (4GB RAM, PCIe, USB 3, 6 cores), which I discovered through their excellent database. https://www.hackerboards.com/search_boarddb.php

The official heat sink is amazing, and can be used together with a PoE hat. That is a huge winner feature for me since the small fans are obnoxiously loud.