Go to advanced search

by ssb22
Sun Aug 05, 2018 1:52 pm
Forum: Debian
Topic: Mounting USB hard drive - unknown filesystem type 'hfsplus'
Replies: 16
Views: 34865

Re: Mounting USB hard drive - unknown filesystem type 'hfsplus'

I ran into this problem recently and it turned out to be because I had upgraded the raspberrypi-kernel package and forgot to reboot. So the version number of the hfsplus module under /lib/modules was the one to match the new kernel I'd just installed, but the actual kernel I was running had an earli...
by ssb22
Thu Nov 14, 2013 5:27 pm
Forum: Advanced users
Topic: Mixing sounds can crash the Pi's kernel
Replies: 6
Views: 1308

Re: Mixing sounds can crash the Pi's kernel

Great that you can reproduce it. Would you be able to open the GitHub issue with details of the kernel panic you got? as I might not be able to rig up the HDMI monitor for a while, and without it I don't have much else to say apart from the above. Thanks.
by ssb22
Thu Nov 14, 2013 1:19 pm
Forum: Advanced users
Topic: Mixing sounds can crash the Pi's kernel
Replies: 6
Views: 1308

Re: Mixing sounds can crash the Pi's kernel

The -c option is telling sox how many channels of sound to generate, so -c 0 does not make sense.

My Pi has been running headless, so I don't know what if anything would have been printed on the monitor. But I can try to rig one up.
by ssb22
Wed Nov 13, 2013 8:52 pm
Forum: Advanced users
Topic: Mixing sounds can crash the Pi's kernel
Replies: 6
Views: 1308

Mixing sounds can crash the Pi's kernel

Hi, the following bash command (which requires sox) crashes my Pi by mixing 4 square waves together on the 3.5mm sound output (my /etc/asound.conf is just pcm.!default hw:0 and I'm using the analogue 3.5mm jack). Usually the Pi crashes on the first call to start_chord, but in the rare case that this...
by ssb22
Tue Nov 05, 2013 5:06 pm
Forum: Advanced users
Topic: Detecting SD card failure
Replies: 7
Views: 3758

Re: Detecting SD card failure

This morning I found an old file (written 2012) corrupted in that a bunch of 0 bytes were written at its end. The only thing that had happened to that directory recently was a chown -R and a chmod -R a+r. My fusecompress script successfully detected the corruption and I restored the old file from ba...
by ssb22
Sun Nov 03, 2013 7:47 am
Forum: Advanced users
Topic: Full specs of onboard sound?
Replies: 11
Views: 12339

Re: Full specs of onboard sound?

Yes HDMI audio is a digital signal so it's up to the receiving device to decode it (if it supports audio, which is not always the case). The receiving device and the sending device need to "negotiate" on which bitrates etc they both support (this is done via the initial EDID request that the Pi send...
by ssb22
Sat Nov 02, 2013 9:29 pm
Forum: Advanced users
Topic: Full specs of onboard sound?
Replies: 11
Views: 12339

Re: Full specs of onboard sound?

Thanks. Incidentally, 11-bit resolution (when used at full range) gives a theoretical signal-to-noise ratio of around 66dB, which, while being lower than the 96dB of 16-bit, is probably still going to be higher than the dB difference between the sound you're playing and the room's noise floor, unles...
by ssb22
Sat Nov 02, 2013 11:20 am
Forum: Advanced users
Topic: Full specs of onboard sound?
Replies: 11
Views: 12339

Re: Full specs of onboard sound?

Thanks. The BCM2835 specs at http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf page 138 says the PWM is "clocked by clk_pwm which is nominally 100MHz but can be varied by the clock manager". I suppose that has to be divided by the number of possible amplitudes it can ...
by ssb22
Sat Nov 02, 2013 10:07 am
Forum: Advanced users
Topic: Full specs of onboard sound?
Replies: 11
Views: 12339

Full specs of onboard sound?

Further to my USB soundcard causing too many problems, and the on-board sound from the 3.5mm jack (when turned up to 100% with amixer) actually seeming a bit better now I have a good power supply (although it's still soft), I put /etc/asound.conf back to pcm.!default hw:0 and am using the on-board s...
by ssb22
Mon Oct 28, 2013 12:24 pm
Forum: General discussion
Topic: Passive speakers
Replies: 24
Views: 50690

Re: Passive speakers

I tried some cheap speakers called Hama MB-20 (don't know the specs) and they work fine when connected to the Pi's 3.5mm jack but they are quiet (the room needs to be quiet to hear them; no use for sounding alerts etc that are supposed to be heard on top of something else). You can get a little extr...
by ssb22
Fri Oct 25, 2013 11:36 am
Forum: Advanced users
Topic: Detecting SD card failure
Replies: 7
Views: 3758

Re: Detecting SD card failure

Thanks. I now have a 2A adaptor (it turned out to be an Apple one, although I didn't know that when I ordered), TP1-TP2 measured 5.32V with nothing connected, dropping to 5.25V with 2 USB devices, and 4.87V when booted and playing sound through a USB soundcard (at reasonably low volume; I wouldn't w...
by ssb22
Thu Oct 24, 2013 6:50 pm
Forum: Advanced users
Topic: Detecting SD card failure
Replies: 7
Views: 3758

Re: Detecting SD card failure

Further to my post above regarding fusecompress, I had a real failure this week due to a faulting power supply, and here are some observations: (I know the problem was the power supply because I used a multimeter to measure the voltage between TP1 and TP2 and found it had dropped to 4.6V, and even w...
by ssb22
Sat May 18, 2013 9:15 pm
Forum: Raspbian
Topic: Magnification in X11 for low-vision users
Replies: 3
Views: 1715

Re: Magnification in X11 for low-vision users

Sorry sanchomuzax, I gave up on this one. My Pi is now being used as a server with no display. Let's hope someone who knows more about the chips' internals sees this.
by ssb22
Sat May 11, 2013 8:22 pm
Forum: General discussion
Topic: How would you use a Raspberry Pi device?
Replies: 514
Views: 209491

Re: How would you use a Raspberry Pi device?

I use mine for running a Web Adjuster server http://people.ds.cam.ac.uk/ssb22/adjuster/ and it's good to be able to do so on such a low-powered device that's also silent so doesn't keep me awake at night in a studio flat. If I ever have to move to a place without broadband, I could ask a friend to t...
by ssb22
Wed Feb 13, 2013 8:12 pm
Forum: Advanced users
Topic: Detecting SD card failure
Replies: 7
Views: 3758

Re: Detecting SD card failure

Thanks for the perl script, that's great if the system is actually detecting and logging the errors, but what I'm trying to do is detect errors that aren't even logged (because I heard there are some SD cards that just flip random bits in your files without even complaining). I found a project calle...
by ssb22
Wed Feb 13, 2013 4:10 pm
Forum: Advanced users
Topic: Detecting SD card failure
Replies: 7
Views: 3758

Detecting SD card failure

I heard rumours that some SD cards do not properly implement wear-levelling and some do not properly report media failure to the OS (despite the fact that there are supposed to be CRC checks going on). I want to be able to detect SD card failure independently of any possibly-malfunctioning SD-card h...
by ssb22
Mon Jan 21, 2013 6:56 pm
Forum: C/C++
Topic: C++ cross compilation from a mac
Replies: 12
Views: 11141

Re: C++ cross compilation from a mac

Thanks. ldd on the Pi just says "not a dynamic executable" when given that .so file. ldd does list dependencies when asked to look at the .so files in /lib, so I don't think this is an ldd limitation, it must be something up with the .so. The "file" command says "ELF 32-bit LSB shared object, ARM, v...
by ssb22
Mon Jan 21, 2013 2:16 pm
Forum: C/C++
Topic: C++ cross compilation from a mac
Replies: 12
Views: 11141

Re: C++ cross compilation from a mac

I should mention that I tried the "lazy" way of (on the Pi) wget http://ftp.uk.debian.org/debian/pool/main/o/openjdk-7/openjdk-7-jdk_7u3-2.1.4-1_armhf.deb ; dpkg -x openjdk-7-jdk_7u3-2.1.4-1_armhf.deb /tmp/openjdk (and on the Mac) cd /Volumes/arm-x ; rsync -purvl YOUR_PI_IP_ADDRESS::pi/tmp/openjdk/u...
by ssb22
Sun Jan 20, 2013 6:23 pm
Forum: C/C++
Topic: C++ cross compilation from a mac
Replies: 12
Views: 11141

Re: C++ cross compilation from a mac

This works great. But does anybody have pointers on how to add more libraries to this toolchain? For example, if cross-compiling a C program that uses the Java Native Interface, how do we fix the "missing jni.h" errors?
by ssb22
Sat Jan 19, 2013 11:41 pm
Forum: Raspbian
Topic: Magnification in X11 for low-vision users
Replies: 3
Views: 1715

Re: Magnification in X11 for low-vision users

A related problem (I believe with the Broadcom VideoCore IV) on HDMI output is: if you set the vertical resolution to half of what the monitor's really is, and specify doublescan, then, instead of cleanly scanning every line twice (giving a crisp low-resolution image), the Broadcom goes and anti-ali...
by ssb22
Fri Jan 18, 2013 10:13 pm
Forum: Raspbian
Topic: Magnification in X11 for low-vision users
Replies: 3
Views: 1715

Magnification in X11 for low-vision users

Hi, I am partially sighted and am trying to get a magnified view in X11 (not just setting all the fonts big, but magnifying everything including bitmaps). On my old PC I can set /etc/X11/xorg.conf with some low-resolution modelines; I can then cycle through the modes using Ctrl-Alt-keypad Plus and i...
by ssb22
Fri Jan 18, 2013 2:12 pm
Forum: HATs and other add-ons
Topic: Another USB sound question
Replies: 11
Views: 15533

Re: Another USB sound question

I don't think the USB audio problem is ARM floating-point by itself, because before I got my Raspberry Pi, I was using an NSLU2 reconfigured as a "Slug" (also running Debian on ARM, but with no video output and only 32M RAM), and I had a cheap unbranded USB sound card configured for it with the foll...
by ssb22
Thu Jan 17, 2013 11:59 am
Forum: C/C++
Topic: Tiny C Compiler (TCC) on Raspberry Pi
Replies: 4
Views: 5313

Tiny C Compiler (TCC) on Raspberry Pi

I downloaded TCC's source at http://bellard.org/tcc/ and changed the "configure" script replacing all 3 instances of armv4l with armv6l, and also edited tcc.h to change /usr/lib to /usr/lib/arm-linux-gnueabihf (compare Debian bug #632089), then I did the usual ./configure && make && sudo make instal...

Go to advanced search