The Raspberry Pi 2 Q&A thread

[jdb]

Somewhat belatedly, here's the official Q&A thread.

Before posting, please read the blog post:

http://www.raspberrypi.org/raspberry-pi-2-on-sale/

and assorted comment responses from Foundation members:

http://www.raspberrypi.org/raspberry-pi ... /#comments

before posting in this thread.

Belated because our website was on fire for pretty much all of the launch day.

[mahjongg]

yeah, i only could get in and do some moderation after midnight!

[DougieLawson]

Belated because our website was on fire for pretty much all of the launch day.

The forum was deliberately blocked from 10:30GMT until 23:30GMT.

[jdb]

Belated because our website was on fire for pretty much all of the launch day.

The forum was deliberately blocked from 10:30GMT until 23:30GMT.

Our website was on fire *despite* load-shedding the forums. Your point?

[DougieLawson]

Belated because our website was on fire for pretty much all of the launch day.

The forum was deliberately blocked from 10:30GMT until 23:30GMT.

Our website was on fire *despite* load-shedding the forums. Your point?

<OFF-TOPIC type="annoyance">
The point being that the Foundation knew they were going to launch today, they could have rented extra capacity from Mythic to support the expected extreme workload (based on extrapolating figures from July (B+) and November (A+)). Removing a significant support resource isn't good for the community.
</OFF-TOPIC>

Normal service is now resumed.

[jdb]

The point being that the Foundation knew they were going to launch today, they could have rented extra capacity from Mythic to support the expected extreme workload (based on extrapolating figures from July (B+) and November (A+)). Removing a significant support resource isn't good for the community.

So for a 13 hour period where the primary purpose of this site was to inform, rather than to discuss, we should have spent at least order of magnitude more on bandwidth, computational resource and logistics to ensure that the discussion platform was available for those precious 13 hours?

As far as I know, RS and element14 do not yet offer same-day delivery (unless you happened to be in London today and spotted a certain bicycle wandering around town). Therefore as a support resource (where discussion is required), having the site available in preference to an informational resource offers little value.

Edit: now that the conflagration is "over" and the load averages on our server are now back down in the sub-1000 range, we can resume normal service.

[TimG]

I'm curious about ARMv6 vs ARMv7. I understand from the announcement that the new CPU can run Raspbian ARMv6 code, but presumably standard Debian ARMv7 code will be faster. Can we switch between Raspbian and Debian repositories without running into problems?

[Lob0426]

Has the Foundation ran any performance tests on the Micro SD and the USB that show improvement?

Though I have not seen any corruption issues with the newest software updates (in more than a year), do you expect any of these issues to reoccur in the new board?

I have seen mention that the USB on chip was not modified. I have not heard much mention about the SD transfers as yet.

[DougieLawson]

The DebIan stuff should run OK. The problem with making that recommendation is that it WILL badly destroy the Raspbian installation for PI1 A,B,A+,B+ users.

[jdb]

Has the Foundation ran any performance tests on the Micro SD and the USB that show improvement?

Though I have not seen any corruption issues with the newest software updates (in more than a year), do you expect any of these issues to reoccur in the new board?

I have seen mention that the USB on chip was not modified. I have not heard much mention about the SD transfers as yet.

uSD generally wasn't CPU limited on 2835.

There was a fix that went in recently that disables CMD23-prefixed transfers - a mode that predefines transfer lengths - there's some complicated state tracking in there that was getting messed up on the fastest of SD cards in extreme circumstances. We encountered this on rare occasions with certain types of SD card, but this became slightly more prevalent on Pi2. We need some bus-level analysis to be carried out before we can safely switch CMD23 back on again.

CMD23 simply allows higher-performing cards to perform faster - the flash controller knows how much data is getting written or read so it can pre-emptively compute which flash pages to open, etc.

USB performance is "better". The software overhead becomes less as you increase CPU power - for instance a USB SSD goes from about 27MB/s on Pi1 to 31MB/s on Pi2.

[jdb]

I'm curious about ARMv6 vs ARMv7. I understand from the announcement that the new CPU can run Raspbian ARMv6 code, but presumably standard Debian ARMv7 code will be faster. Can we switch between Raspbian and Debian repositories without running into problems?

Currently the ARMv6 userland (Raspbian et al) is default.

Once we do some performance comparisons (v6 versus v7 compiled libraries/binaries etc) then we may decide to:
- Have a v6 userland as performance improvements are negligible
- Have a hybrid v6 / v7 userland that takes advantage of parallelism at the library level (dynamically selected at boot-time)
- Transition to a v7 userland (least desirable, mandates separate SD card images).

As yet there is insufficient data to formulate a plan. Raspbian is our officially supported OS and will remain so.

[mckenzba]

Since the new BCM2836 is a Cortex-A7 chip and we know it supports neon (and presumably vfpv4-d32/udiv/sdiv), does this chip also support hardware virtualization? (It would be really cool to run xen on this thing!)

[jdb]

Since the new BCM2836 is a Cortex-A7 chip and we know it supports neon (and presumably vfpv4-d32/udiv/sdiv), does this chip also support hardware virtualization? (It would be really cool to run xen on this thing!)

The Cortex-A7 architecture has built-in support for Hypervisor modes and some tricks that make virtualisation "easier".

Further reading:

http://www.slideshare.net/xen_com_mgr/h ... processors

[gdw35]

I currently have a Model B that I have set up for media and gaming, as well as a bit of development (also have LCD display attached). I was hoping I could just swap this out for the Pi 2. Am I able to just copy the SD card I am using for the Model B to a micro -SD for use on the Pi 2, or do I need to start from scratch again and set it all up again?

If I can just copy the SD card is there anything I need to do or change after booting the first time (i.e. config changes, setup, etc.)?

Thanks.

[jdb]

I currently have a Model B that I have set up for media and gaming, as well as a bit of development (also have LCD display attached). I was hoping I could just swap this out for the Pi 2. Am I able to just copy the SD card I am using for the Model B to a micro -SD for use on the Pi 2, or do I need to start from scratch again and set it all up again?

If I can just copy the SD card is there anything I need to do or change after booting the first time (i.e. config changes, setup, etc.)?

Thanks.

To use an existing card on Pi2 you need
- Recent firmware
- kernel7.img
- ARMv7 kernel modules.

To upgrade an SD card for Pi 2 use:
sudo apt-get update && sudo apt-get upgrade

[plugwash]

Are there new config.txt parameters to allow seperately specifying armv6 and armv7 kernels/initrds ?

[Applicable_Robotics]

Does the foundation have a time frame for the release of the Compute Module 2?
Also, have you considered making a version of the compute module that uses a microSD card instead of a fixed size eMMC chip? That also might eliminate the eMMC disable circuit?
Maybe another solution is using a header similar to the one on the Intel Edison as a storage connector.
I think a lot of applications would benefit from allowing the user to increase the size of the storage as needed.
Nicholas

[psergiu]

Will MPEG2 and VC-1 licences still be needed for hardware-decoding ?
Or is the new quad-core CPU fast enough that it would not matter anymore ?

Thanks.

[gdw35]

To use an existing card on Pi2 you need
- Recent firmware
- kernel7.img
- ARMv7 kernel modules.

To upgrade an SD card for Pi 2 use:
sudo apt-get update && sudo apt-get upgrade

Thanks for reply.

So prior to copying card do the update and upgrade to ensure all up to date and then repeat after running up copy on new Pi?

[rpiswag]

Can I over clock the new Raspberry Pi 2 model B? Can I overclock it to 1.2ghz or higher? I was wondering this because windows 10 is quite intensive especially on a Raspberry Pi and overclocking would make windows run smoother.

[Efcis]

According to other posts, Win10 for Pi2 won't have any GUI. Can you confirm ?

And what about the Ubuntu distro for the Pi2 ?

Thanks !

[ric96]

will their be support for android (unofficially, i know their wont be any from the foundation itself) now that the hardware is more than capable?

[ktb]

will their be support for android (unofficially, i know their wont be any from the foundation itself) now that the hardware is more than capable?

Since you know that Android on the Pi2 will be unofficial if it happens, how can that be answered by any person right now? If you build it, they will come.

[ktb]

According to other posts, Win10 for Pi2 won't have any GUI. Can you confirm ?

And what about the Ubuntu distro for the Pi2 ?

Thanks !

Everything I've seen about Win10 IoT suggests that it is all CLI. Maybe the Pi2 can run (limited?) GUI apps that have been deployed to it though? I haven't found any certain information.

I've seen a couple seemingly relevant Ubuntu Snappy Core demo videos on YouTube. Those seemed to only demonstrate using it as a cloud server with remote web GUIs.

I'd like to know more too.

[Nightwing2012]

Cannot find this item...

Will the RPI 2 handled above 32GB SDHC style cards.

Tnks for any information!