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by Electron752
Tue Mar 29, 2016 5:39 pm
Forum: Bare metal, Assembly language
Topic: Entering aarch64 execution state
Replies: 171
Views: 77906

Re: Entering aarch64 execution state

Hi, I got my RPI 3 a few days ago. I'm able to build u-boot for 64 bit and it runs just fine. I can see the text on the monitor and everything seems great. I am having a ton of trouble getting the serial port to work on RPI 3. I've tried all the overlay recommendations without any success. No text t...
by Electron752
Wed Mar 16, 2016 4:06 am
Forum: Bare metal, Assembly language
Topic: Entering aarch64 execution state
Replies: 171
Views: 77906

Re: Entering aarch64 execution state

marcus_c:

That's really cool. I didn't realize it was possible to get a bootable kernel with such a small number of changes. My PI 3 is on back order right now, but I will certainly be testing this as soon as I get it.
by Electron752
Tue Mar 15, 2016 12:27 pm
Forum: Bare metal, Assembly language
Topic: Entering aarch64 execution state
Replies: 171
Views: 77906

Re: Entering aarch64 execution state

Hi, I've been doing some reading of web pages and it appears that 64 bit ARM may not be that easy since there are some pointer dependencies between the firmware, bootloader, and linux kernel. I was wondering if anybody has any thoughts on getting a 64 bit compile of the linux kernel running with the...
by Electron752
Mon Feb 01, 2016 2:50 pm
Forum: Raspbian
Topic: Getting linux kernels >4.1 to boot
Replies: 1
Views: 389

Re: Getting linux kernels >4.1 to boot

Just wanted to add that I think I solved this.

The standard install command of "make install modules_installl" is producing a corrupt/incomplete initrd file. If after install I manually delete the initrd file and recreate it with "update_initramfs -c -k <version>" then the new kernel boots.
by Electron752
Mon Feb 01, 2016 4:14 am
Forum: Raspbian
Topic: Getting linux kernels >4.1 to boot
Replies: 1
Views: 389

Getting linux kernels >4.1 to boot

For various reasons I'm building the PI linux kernel from github.com/raspberrypi/linux from source. I can easily get 4.1 to build and boot just fine with the default configuration(bcm2709_defconfig). But for some reason, I can't get any of the newer branches to boot with the default configuration. M...
by Electron752
Sun Jan 31, 2016 5:57 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Trouble using isosynchronous USB transfers from RPI 2
Replies: 7
Views: 917

Re: Trouble using isosynchronous USB transfers from RPI 2

I suspected this was a limitation of the rpi hardware. Thanks for being honest and upfront. Like I said, I actually found a work around so I'm not too worried about it at this point. It just requires using twice the bandwidth. I was still seeing the problem with a 256 byte transfer size. I'm a bit s...
by Electron752
Sat Jan 30, 2016 5:20 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Trouble using isosynchronous USB transfers from RPI 2
Replies: 7
Views: 917

Re: Trouble using isosynchronous USB transfers from RPI 2

Before I go filing detailed bug reports and providing all kinds of details, is it possible this is simply a known issue that the SOF can/does stomp on transfers? I'm more then happy to file bugs and perhaps even help with a code change fix, but I don't want to waste a bunch of time if it isn't going...
by Electron752
Sat Jan 30, 2016 6:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Trouble using isosynchronous USB transfers from RPI 2
Replies: 7
Views: 917

Re: Trouble using isosynchronous USB transfers from RPI 2

I put the RPI 2 on a USB bus analyzer and I think I have a better understanding of what is happening. It appears that the linux kernel of the RPI 2 is not correctly scheduling the ISO transfers around the SOF token that happens every 1ms. After a few seconds, the time that the transfer happens durin...
by Electron752
Thu Jan 28, 2016 12:35 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Trouble using isosynchronous USB transfers from RPI 2
Replies: 7
Views: 917

Trouble using isosynchronous USB transfers from RPI 2

I have a custom made LED panel based display that I've made that attaches to the RPI 2 via USB. The display is controlled via a custom C daemon that uses libusb-1.0 to control the display. 40 times per seconds the display is refreshed using rather high bandwidth isosynchronous USB transfers to an IS...
by Electron752
Wed Aug 12, 2015 3:34 pm
Forum: Raspbian
Topic: Linux kernels newer then 3.18
Replies: 3
Views: 682

Re: Linux kernels newer then 3.18

Thanks. The links helped a bunch.

This link also helped:
https://www.raspberrypi.org/documentati ... uilding.md
by Electron752
Wed Aug 12, 2015 2:16 am
Forum: Raspbian
Topic: Linux kernels newer then 3.18
Replies: 3
Views: 682

Linux kernels newer then 3.18

Is it possible to use Linux kernels newer then 3.18 on a RPI 2? If a port isn't available, is a port in the works? I use stock debian on my RPI 2(Not Raspbian). In the past with up to 3.18 I was able to take the kernel source from the raspbian archive and recompile it on debian using raspbian's kern...
by Electron752
Thu Mar 05, 2015 6:49 am
Forum: Bare metal, Assembly language
Topic: BCM 2836 and the RPi 2 ?
Replies: 95
Views: 28985

Re: BCM 2836 and the RPi 2 ?

I think they were figuring about 1 Million have went to children. The rest are Hackers, Makers, Experimenters etc...... That's actually rather impressive and cool. If I understand it correctly, that about 20% going to the intended audience. Like I said, not bad. But it also illustrates the point I ...
by Electron752
Thu Mar 05, 2015 2:35 am
Forum: Bare metal, Assembly language
Topic: BCM 2836 and the RPi 2 ?
Replies: 95
Views: 28985

Re: BCM 2836 and the RPi 2 ?

Intensive high level programming (whatever that actually is) is perfectly possible on a Pi, but that isn't really the point. Education isn't about intensive high level programming. It's about teaching and getting the equipment to teach in to the hands of the people who need it. $35 is less than $20...
by Electron752
Tue Mar 03, 2015 6:54 am
Forum: Raspbian
Topic: Raspbian Source code
Replies: 3
Views: 1375

Re: Raspbian Source code

Naveen, You can get most of the source code for Raspian with the "apt-get source" command for most components. It will download the upstream source code and apply any Debian and Raspbian specific patches to it. You can usually compile the component just by typing make from the command prompt. It doe...
by Electron752
Tue Mar 03, 2015 6:45 am
Forum: Bare metal, Assembly language
Topic: BCM 2836 and the RPi 2 ?
Replies: 95
Views: 28985

Re: BCM 2836 and the RPi 2 ?

I'm relatively new to the PI and I'm a bit hesitant at making this post... If the goal of the PI is education for high level programming, what is the PI solving that a $200 - $300 cheap PC or laptop running Debian Linux does not. Is it really to sell computers to poor children that can't afford a PC...
by Electron752
Tue Mar 03, 2015 6:32 am
Forum: Raspbian
Topic: Using normal Debian repos with Raspberry Pi 2
Replies: 3
Views: 1569

Re: Using normal Debian repos with Raspberry Pi 2

After thinking more, it appears that the piece I'm missing is the X windows user mode video driver. It appears that X windows is currently using the bare bones frame buffer driver. Does a X Window driver exist for videocore, or has most of the Raspbian effort been to modify individual applications t...
by Electron752
Mon Mar 02, 2015 7:31 pm
Forum: Raspbian
Topic: Using normal Debian repos with Raspberry Pi 2
Replies: 3
Views: 1569

Re: Using normal Debian repos with Raspberry Pi 2

In a somewhat convolution way, I was able to get a full distribution of plain Debian Jessie to work on the PI 2. The only problem I have is that I can't get video hardware acceleration to work using stock Debian. Is this a known issue with the PI 2? Specifically, I can't get some of the apps from De...

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