In the 2.1 revision the priority registers have been improved. In the
old version there was a bug: all peripherals used the bits of one
register, the other was unused. Now they are properly connected, but the
default values of peripheral priorities are thus not the same as the old
1.3 silicon.

To restore the previous 1.3 priority situation our bootloader just
writes V1.3 equivalent values into both registers.

Maybe this is also your problem.

Kind regards,
Arie de Muijnck


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On
Behalf Of DISTEC Kloiber Thomas
Sent: Tuesday, March 23, 2010 15:38
To: [email protected]
Subject: Audio dropouts since using DM6443 silicon rev. 2.1

Hi,

I have a custom board with DaVinci DM6443 with kernel TI LSP 2.0.0.140
(MV 2.6.18), DVSDK 2.0.0.22 and TI gStreamer for video / audio playback.
In parallel to the playback there is a HTTP and a FTP server running on
the ARM. The HTTP server is used to configure the board via web browser
and the FTP server is used to do content uploads.

Now I received the first boards with silicon rev 2.1 (TMS320DM6443A).
All these boards have the same problem. 
When the HTTP server (as long as the user is configuring the board) or
FTP server (as long as the user is uploading new content) is working in
parallel to video playback, I get audio dropouts at the line out. Just
doing video / audio playback works fine. 
I guess, this has something to do with the extra system load caused by
the servers. Playing around with nice levels of the servers did not
help.

I don't have this problem with silicon revision 1.3. The only difference
between both systems is just the silicon rev. of the DaVinci (same
hardware, same firmware).

I found this in the Silicon Errata:
http://focus.ti.com/lit/er/sprz240m/sprz240m.pdf
Page 8: 2.1.3 Audio Serial Port (ASP) Transfers Should be Buffered in
Internal Memory


For me it seems, this issue might be the root cause for the problem I
came across?
I guess, TI LSP doesn't use the internal memory to buffer audio? At
least I didn't find it...
I currently don't understand, why I have this problem with silicon rev
2.1 only. Does this make sense?

In the archive of this list I found some patches for git kernel, which
introduced usage of internal memory to avoid underrun on audio.

I guess, this is what have to implement on my kernel as well?

Has anyone done this before for MV 2.6.18 ?

Unfortunately, I don't have the resources to switch to the git kernel at
the moment. And AFAIK, video playback on DM644x is still not supported
by TI DVSDK with git kernel.

Thanks in advance!

Kind regards
Thomas
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