Raspberry Pi Forums

summers

Interesting article. Yes I can see why the set -msoft-float now. Logic a bit convoluted. Guess its just strongly encouraging people not to use floats in the kernel, which I guess could be more transparanetly done by one of the coding rules for the kernel.

summers

Noticed something odd last night, when compiling a plain vanilla linux kernel for my panda board. My default gcc is hard float, but passing V=1 to the make command could see -msoft-float was being defined. Turns out its defined that way in arch/arm/Makefile. So just wondering if the same issue is th...

summers

George

summers

Isn't NEON only implemented in cortex-a8 and cortex-a9, didn't think it was available in arm11 ....

e.g. are you sure neon is available on the RPi?

summers

One the size of the partiation has been increased on the SD card, a DD of the raw image will give rather a large file. If you want to save some space, instead just take a copy of the files, so something like: cd /path/to/root tar cf ../debian.tar . then probably compress the result bzip2 debian.tar ...

summers

Something else to add. When booting the kernel pass the argument "console=whatever" Where /dev/whatever is the device file of the serial line you are watching ... Kernel takes a short time to get far enough though to be able to direct messages to the console though - so you may not get a m...

summers

Suspect this isn't where raspbian is at right now - its still alpha/beta software. Means that at the moment it probably going to be a bit clunky. So first time users probably better off by using one of the other builds. Of course Rasbrian is aiming at how to get the best out of the RPi hardware - so...

summers

when I compile a cross compiler (I do it from scratch, so using gcc, binutils, uClibc), I normally do: --target=armv7-hardfloat-linux-gnueabi --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu so give the full name, and for me specify host and build (as well as target) as I compile and run the c...

summers

Yup, and this work is still on-going too: https://github.com/raspberrypi/linux Ta - thanks, most interesting post so far. Hard to dig into github - but shows activity, which is good. Odd how much is focsued on the GPU - yes I guess its what most people are interested in - but there is so much more ...

summers

# pi.py - calculates the constant pi (the ratio of the circumference to the diameter of a circie) # to any arbitrary number of digits # Usage: python pi.py number_of_digits - e.g., to calculate pi to 100 digits of accuracy, python pi.py 100 # This program uses Machin's formula (per John Machin circ...

summers

Just noticed that Rob Clark of TI (well seems he's also linarno) has a blog. Its worth reading his post of Saturday, April 14, 2012 - just his view of someone hacking about with arm based boards, and more relevent someone doing something about it: http://bloggingthemonkey.blogspot.co.uk/ I guess the...

summers

I think thats why I wanted to talk far wider than just GPU software interafces to hardware interfaces. As GPUs are a complex area. So lets back off a bit. The operating system that is based to run on the RPI is GNU/Linux - both open source developments. The open source nature of both GNU and Linux i...

summers

@summers I'm not sure if I am understanding you correctly, but dom and the others (so far as i know) are trying to open-source the userspace libraries (OpenVG , OpenMAX , OpenGL etc.). As usual no promises , no ETA. Yes that was what I'm asking, what open source activity specific to RPi hardware is...

summers

But MOST video codecs are proprietary!! When you play video in XYZ format, that format is the Intelectual Property of someone and you have to pay that someone to use it. There are people who develope "converters" that change XYZ format to play on your ABC device, but most of the time that...

summers

You seem to be missing the point. We have the driver for the GPU. What we are missing are some of the codecs for decoding video formats. Do you get the difference? It isn't a question of Broadcom giving them to us. Broadcom doesn't own them. In order for Broadcom to implement them for the RPi someo...

summers

I think one of the differences is that TI is much more supportive of the "hobbyist market" - their chips are available in small volumes. But Broadcom is geared up much more towards the industrial/mobile phone market - their chips are only available in large volumes. But from what's been s...

summers

I'll start off by saying that I'm not having a go at anyone here - the world is the way it is, and lets live with it. Anyway, the question, linux is only just starting out in a big way on arm cpus, so comparing it to the x86 linux its going though much of what x86 did 15 years ago or so. Mainly I'l ...

summers

FollowingGhosts wrote:I tried all night last night, but HDParm kept giving me errors ...

what errors out of interest

I've usually found errors are bcause the HDD doesn't support some options ...

summers

Yes hdparm is he way to do this. Can make things a tad unstable, when the OS tries to access the hard disk, and it needs to spin up first, things time out. There are various flags you can pass, -y -Y -s -S, read the man page. Not all hard drive take all options - but you might as well try. Usually s...

summers

If you want to go in the JTAG direction, then you'll need to get something like a pandaboard, and the JTAG dongle isn't cheap either .... Now you'll be able to get the same code inro the ARM be writing fictional kernel images and writing to SD, as using the JTAG. It isn't clear if the arm comes up i...

summers

dom said:

@summers
cmdline.txt is written by GPU blob to space allocated for "ATAGs" inside the kernel image (at 0x100). The kernel *will* see the command line arguments.

OOps yes - i was think of config.txt ....

summers

<t>Mjiig said: Regarding the arguments that was new to me. How does the kernel get at it's options then? (GRUB I think allows passing of "command line" options to linux, and on the RiPi that appears to be the point of cmdline.txt). Probably the easiest way is to co...

summers

<r>hzrnbgy said: If you fancy reading datasheets from the manufacturers regarding their PSUs ripple, efficiency levels, etc, nothing beats good 'ol mouser.com <URL url="http://www.mouser.com/Power/Pl.....fmZ1z0wda9">http://www.mouser.com/Power/Pl.....fmZ1z0wda9</URL><br/...

summers

<t>I find it hard to see the point of two pi's. Look at the specs of: RPi -> Beagleboard (bone) -> Pandaboard Both prices and processing power go up as you move the the right. So if you need a machine with more grunt - wouldn't you just buy a board to the right, rather than 2 ...

summers

<r>Check the linux from scratch web site: <URL url="http://www.linuxfromscratch.org/">http://www.linuxfromscratch.org/</URL> Whilst it doesn't explain exactly what you want to do (e.g. they are building something that will run on the same machine you are building on) - it does explain the...

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Hard Float kernel for Rasbrian

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