Hi,
I just checked with our system verification guys and they have had a DM355
(running this kernel) playing out audio since Friday without issue (so that
would be >48 hours) so it can be made to work.
We incorporated some advice given to us by a MV engineer into our framework,
which may be the reason we don't see any issue. This included..
*
Write to device only in fragment sized chunks.
*
Read from device only in fragment sized chunks and empty input if
possible.
*
Choose fragment size to match data rate. In OSS, fragments are a 'power
of 2' - we need to read/write in 10 or 20 msec chunks for VOIP speech codecs.
Fragment size needs to be as close to 10msec @ whatever speed/channels/sample
size is used, typically 256 bytes for 16 bit, 8kHz mono. Some drivers default
to 4k, which is fine for 44.1kHz half duplex playback. However it adds a huge
delay when used full duplex @ 8khz.
*
When in full duplex mode you need to treat input & output as seperate
items.
*
Avoid 'blocking' read/write functions as you may 'starve' the other
operation. Use the input/output space OSS ioctls to see if the driver has space
for output or samples for input - this avoids blocking as you skip the read or
write if there is no output space or input data available.
Regards
Phil Q
Regards
Phil Q
Phil Quiney, Principal Software Engineer
Trinity Convergence
Cambridge Business Park
Cowley Road
Cambridge CB4 0WZ, UK
T: +44(0)1223-435536
F: +44(0)1223-435560
www.trinityconvergence.com <http://www.trinityconvergence.com/>
________________________________
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of amingaming
Sent: 13 October 2008 06:01
To: davinci-linux-open-source@linux.davincidsp.com
Subject: mvl_4_0_1_demo_lsp_setuplinux_01_20_00_014.bin for DM355 ?
hi all:
I dowanLoad mvl_4_0_1_demo_lsp_setuplinux_01_20_00_014.bin form www.TI.com
for DM355.
start run DM355 OK,after some times,no Sound! why ?
thx
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