Messages in this thread | | | Date | Fri, 3 Feb 2012 09:37:48 +0100 | Subject | [dmaengine] [Q] jiffies value does not increase in dma_sync_wait() | From | javier Martin <> |
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Hi, I have a Visstrim_M10 board, based on i.MX27, and I'm developing a v4l2 driver for deinterlacing video frames.
Whenever I start a new dma transfer I call the function "dma_wait_for_async_tx()" which internally ends up calling "dma_sync_wait()":
http://lxr.linux.no/#linux+v3.2.2/drivers/dma/dmaengine.c#L255
In this function, there is a "do while" loop, which checks for dma completion, with a timeout. However, when the system is too loaded this function enters this "do while" loop and never gets out of it, blocking the system.
I've introduced a couple of printk() to check why this timeout is not triggered and I've found that the value of jiffies does not increase between loop iterations (i. e. it's like time didn't advance).
Does anyobody know what reasons could make jiffies not being updated?
Regards. -- Javier Martin Vista Silicon S.L. CDTUC - FASE C - Oficina S-345 Avda de los Castros s/n 39005- Santander. Cantabria. Spain +34 942 25 32 60 www.vista-silicon.com
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