2009-04-16 07:14:07     sometimes the PPI DMA transfer never start

Document created by Aaronwu Employee on Aug 14, 2013
Version 1Show Document
  • View in full screen mode

2009-04-16 07:14:07     sometimes the PPI DMA transfer never start

Jean-Francois Argentino (FRANCE)

Message: 72745   

 

Hello again.

 

This is the following of the thread #71887 I've started there's some days now, but as it looks dead and I've made some new constatations, I hope somebody could explain to me what could happen...

 

So I've implemented a PPI driver (the one that exists now where not enough usable when I've started to play with PPI, and more over I need to internally generate frame sync signals). And strangely, sometimes, the DMA transfer never start... I was thinking that it never rise the interrupt at its end, but In fact, if I'm using "wait_event_interruptible_timeout" instead of "wait_event_interruptible" in the "read" function of my driver, when the timeout expires I can see old data in the receiving buffer... This problem occurs for about once every 100000 successful transfers... and not on every board I've tested: on 3 boards it works great for long time (24 hours with a transfer every 1.4ms), but it fails for 7 other boards.

 

It's not the only one problem I've got with these boards (Bluetechnix CM-BF537E with DSP rev0.3) on uClinux (SVN trunk): you can see two other threads i've started yesterday, and as the release date of my project gets closer, I really intersted by any ways to look at. For now, i'll try to do the same thing under VDK and see the result...

 

bfin_ppi.h

bfin_ppi.c

TranslateQuoteReplyEditDelete

 

 

2009-04-16 07:21:04     sometimes the PPI DMA transfer never start

Michael Hennerich (GERMANY)

Message: 72746    In your driver did you request the PPI_ERROR IRQ?

It's likely that the PPI_ERROR IRQ triggers instead of the DMA done IRQ.

 

-Michael

 

 

QuoteReplyEditDelete

 

 

2009-04-16 07:30:46     Re: sometimes the PPI DMA transfer never start

Jean-Francois Argentino (FRANCE)

Message: 72748   

 

I'm requesting the PPI_ERROR_IRQ and the DMA_ERROR_IRQ, and none rise...

Attachments

Outcomes