Besides adapting the components to the use of base/log.h, the patch
cleans up a few base headers, i.e., it removes unused includes from
root/component.h, specifically base/heap.h and
ram_session/ram_session.h. Hence, components that relied on the implicit
inclusion of those headers have to manually include those headers now.
While adjusting the log messages, I repeatedly stumbled over the problem
that printing char * arguments is ambiguous. It is unclear whether to
print the argument as pointer or null-terminated string. To overcome
this problem, the patch introduces a new type 'Cstring' that allows the
caller to express that the argument should be handled as null-terminated
string. As a nice side effect, with this type in place, the optional len
argument of the 'String' class could be removed. Instead of supplying a
pair of (char const *, size_t), the constructor accepts a 'Cstring'.
This, in turn, clears the way let the 'String' constructor use the new
output mechanism to assemble a string from multiple arguments (and
thereby getting rid of snprintf within Genode in the near future).
To enforce the explicit resolution of the char * ambiguity, the 'char *'
overload of the 'print' function is marked as deleted.
Issue #1987
There are currently some issue with the mixing/filtering code of vbox.
So instead of using the audio subsystem to do filtering and mixing we
bypass it to get better audio qualitiy. That means that the device
model of the VM has to use the same sample rate as the Audio_out/in
sessions, however.
Issue #1647.
With this commit preliminary audio support in VirtualBox is enabled.
The backend supports playback as well as recording sounds from within
a guest VM. Depending on how the guest configures the device model
the audio output may sound disorted. If the guest uses buffers that
are too small, i.e., 10 ms or less, frequent buffer underruns will
occure.
To get this low-latency one has also to increase vbox' update hz
to 200 (i.e., 5ms).
Fixes#1647.
