Hi Laurent, On 07/20/2011 10:47 AM, Laurent Pinchart wrote: > > Hi Michael, > > Sorry for the late reply. Likewise :) > > On Thursday 30 June 2011 10:31:52 Michael Jones wrote: >> Hi Laurent, >> >> I'm observing a system freeze-up with the ISP when writing data to memory >> directly from the ccdc. >> >> Here's the sequence I'm using: >> >> 0. apply the patch I'm sending separate in this thread. >> >> 1. configure the ISP pipeline for the CCDC to deliver V4L2_PIX_FMT_GREY >> directly from the sensor to memory. >> >> 2. yavta -c10 /dev/video2 >> >> The patch is pretty self-explanatory. It introduces a loop (with ugly >> indenting to keep the patch simple) with 100 iterations leaving the device >> open between them. My system usually hangs up within the first 30 >> iterations. I've never made it to 100 successfully. I see the same >> behavior with user pointers and with mmap, but I don't see it when using >> data from the previewer. >> >> Can you please try this out with your setup? Even if you can't get 8-bit >> gray data from your sensor, hopefully you could observe it with any other >> format directly from the CCDC. >> >> I'll postpone further discussion until you confirm that you can reproduce >> the behavior. As the patch illustrates, it looks like it is hanging up in >> STREAMON. > > I've tested this with a serial CSI-2 sensor and a parallel sensor (MT9V032, in > both 8-bit and 10-bit modes, albeit with SGRBG8 instead of GREY for the 8-bit > mode), and I can't reproduce the issue. > > I thought I've asked you already but can't find this in my mailbox, so I > apologize if I have, but could you try increasing vertical blanking and see if > it helps ? > I think that was the first time you suggested that. Indeed, if I stretch out the time between frames, the problem goes away. I haven't tested it precisely to see how long it needs to be to work correctly. But what does this tell me? This isn't a very appealing fix as 1) I would have to fish around for a minimum vertical blank time that works and 2) this would slow down the frame rate for the normal case, when frames are just being streamed uninterrupted. -Michael MATRIX VISION GmbH, Talstrasse 16, DE-71570 Oppenweiler Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschaeftsfuehrer: Gerhard Thullner, Werner Armingeon, Uwe Furtner, Erhard Meier -- 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
