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Difference between revisions of "RPi Bugs"

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m (Hardware: changed link formatting)
(Hardware: Clarified audio click event)
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* The current R-Pi firmware limits users to 2 hubs and 14 ports.
 
* The current R-Pi firmware limits users to 2 hubs and 14 ports.
 
* Some Hardware is unsupported [[RPi_VerifiedPeripherals|link]]
 
* Some Hardware is unsupported [[RPi_VerifiedPeripherals|link]]
* The sound output port on boards version 1.0 and 2.0 are miss-wired causing distortion and a DC offset which could damage certain types of DC-coupled amplifiers and even loudspeakers. It is recommended that you use the HDMI or I2S functionality. If you need to use this port, make sure that the equipment you use has a DC blocking capacitor. The specific problem is that the surge suppression network, which should come between the SoC and the DC blocking capacitor comes AFTER the capacitor, creating a rectification effect of the signal, causing a DC offset and distortion. The design fix is simple, move the DC blocking capacitor after the surge suppressing diodes and then add a 100k resistor (470k, or even up to 1M is fine too) to ground. A series 100 ohm resistor just before the jack might also help suppress unwanted RF interference. If high quality output is required from existing boards, it is necessary to remove parts D12 and D13 from the back of the board. The three pads should be VCC, signal and GND respectively, identify each pad and carefully install some resistor between 10k and 100k between the signal and GND, making sure not to short out VCC. This is fairly high-end SMD re-work, I would suggest you get some training, tools and practice before attempting. (ed note: the writer of this comment does not have said skills, only knows what would have to be done).
+
* The analog sound output chip suffers from a clicking problem when it awakes from sleep.
 +
: This is caused by the quiet signal sitting at half rail when the chip is active and the signal
 +
: sitting at ground when the chip is asleep. During the wake/sleep process the analog output is rapidly
 +
: driven between these two levels causing an annoying, but not damaging, click.
 +
: Recent versions of software drivers have accounted for this problem by being far less aggressive in putting
 +
: the audio DAC to sleep.
  
 
= Software =
 
= Software =

Revision as of 03:40, 25 April 2013


See R-Pi_Troubleshooting for problems that are not bugs.

Hardware

  • The current R-Pi firmware limits users to 2 hubs and 14 ports.
  • Some Hardware is unsupported link
  • The analog sound output chip suffers from a clicking problem when it awakes from sleep.
This is caused by the quiet signal sitting at half rail when the chip is active and the signal
sitting at ground when the chip is asleep. During the wake/sleep process the analog output is rapidly
driven between these two levels causing an annoying, but not damaging, click.
Recent versions of software drivers have accounted for this problem by being far less aggressive in putting
the audio DAC to sleep.

Software

(excluding non-official distribution specific bugs)

OS

Kernel

Firmware