Hi, On Wednesday 07 September 2011 12:10:23 Koyamangalath, Abhilash wrote: > On Tue, Aug 30, 2011 Laurent Pinchart wrote: > > On Wednesday 10 August 2011 16:03:12 Deepthy Ravi wrote: > >> From: Abhilash K V <abhilash.kv@xxxxxx> > >> > >> 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 ? > > Yes, I believe this issue would crop with preview and resizer too though I > have not been able to try these out. That's my belief as well. In that case the fix should be generic, not CCDC- specific. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
