On Tue, Aug 30, 2011 Laurent Pinchart wrote: > Hi, > > On Wednesday 10 August 2011 16:03:12 Deepthy Ravi wrote: >> From: Abhilash K V <abhilash...@ti.com> >> >> While resuming from the "suspended to memory" state, >> occasionally CCDC fails to get enabled and thus fails >> to capture frames any more till the next suspend/resume >> is issued. >> This is a race condition which happens only when a CCDC >> frame-completion ISR is pending even as ISP device's >> isp_pm_prepare() is getting called and only one buffer >> is left on the DMA queue. >> The DMA queue buffers are thus depleted which results in >> its underrun.So when ISP resumes there are no buffers on >> the queue (as the application which can issue buffers is >> yet to resume) to start video capture. >> This fix addresses this issue by dequeuing and enqueing >> the last buffer in isp_pm_prepare() after its DMA gets >> completed. Thus,when ISP resumes it always finds atleast >> one buffer on the DMA queue - this is true if application >> uses only 3 buffers. > > How is that problem specific to the CCDC ? Can't it be reproduce at the > preview engine or resizer output as well ? [Abhilash K V]Yes, I believe this issue would crop with preview and resizer too though I have not been able to try these out. > > -- > Regards, > > Laurent Pinchart >
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