[Bug 353968] [NEW] USB DVB-T devices unusable on EPIA-M system under Jaunty unless cpufreq scaling (longhaul?) disabled

[Dominic Evans]

Public bug reported:

I am using an EPIA-M mini-itx box as a vdr system using a DVB-T tuner
over USB.

Both live TV and recordings are unstable with clicking and popping sound
as well as a breaking up picture unless cpufreq scaling is disabled by
running the following script:

{{{

#!/bin/sh

MAX_FREQ=`cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq`

echo $MAX_FREQ > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
echo $MAX_FREQ > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
echo $MAX_FREQ > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq

}}}

This effectively disables any cpufreq (longhaul?) changes being made
during operation. Though it is not ideal as there is obviously a large
amount of time when the system can remain idle on low-cpu to save
voltage/energy.

Whilst playing back TV, the current CPU speed is identified as being the
maximum, but there is obviously some polling going on underneath the
covers that is causing problems.

Let me know if you need any further info.

ProblemType: Bug
Architecture: i386
Dependencies:
 
DistroRelease: Ubuntu 9.04
Package: linux-image None [modified: /var/lib/dpkg/info/linux-image.list]
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-meta
Uname: Linux 2.6.28-11-generic i686
UnreportableReason: This is not a genuine Ubuntu package

** Affects: linux-meta (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386

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USB DVB-T devices unusable on EPIA-M system under Jaunty unless cpufreq scaling (longhaul?) disabled
https://bugs.launchpad.net/bugs/353968
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