Hi Sergio, On Friday 03 December 2010 01:32:08 Aguirre, Sergio wrote: > On Thursday, December 02, 2010 11:34 AM Lane Brooks wrote: > > On 12/02/2010 07:35 AM, Laurent Pinchart wrote: > > [snip] > > > > > > Any ideas on the problem? Is there a way to force a reset to the CCDC > > > > so that it will become IDLE? > > > > > > Would you expect the ISP to recover gracefully if you removed the > > > OMAP3530 or the RAM from the board and plugged it back ? The same > > > applies to the sensor :-) > > > > > > Long story short, once started, the CCDC can't be stopped before the > > > end of the image. When you unplug the sensor the CCDC will wait forever > > > for the end of frame. When restarted it will resume working to the > > > previous, no longer mapped buffer, leading to IOMMU faults. > > > The CCDC, like most ISP blocks, can't be reset individually. You need > > > to reset the whole ISP to recover from this (blame whoever decided that > > > individual block resets were not useful). This was done before on > > > streamoff, but now that the ISP driver supports running multiple > > > pipelines in parallel we can't do it anymore. > > > > > > It might be possible to write a clean patch to reset the ISP when all > > > streams are stopped. In the meantime you can rmmod/modprobe the driver. > > > > Laurent, > > > > Thanks for the feedback. The behavior makes perfect sense now. I can > > take it from here. Given the user *can* unplug the sensor module in our > > hardware, I need to do something, as locking up the kernel is not > > acceptable. I will first look to see if an ISP reset on stream off > > works, as we can sacrifice multiple pipeline support (for now). > > Laurent, > > Just a question on this: > > Do we ever plan to support dynamic v4l2_subdevs > registration/unregistration? > > I guess we'll require to "notify" the media controller device, so we add > it, (or remove it) from the pipeline, and refresh the links. > > I think that is going to become an important requirement, as like Lane is > doing (unloading a module). > > It's very likely that we can interchange camera modules, like in the > Beagleboard xM, and we don't have a real reason to really not support > that. > > It would be very cool to be able to: > > 1. Plug Aptina 5MP camera sensor. > 2. Load the kernel module > 3. Use the camera > 4. Unload the kernel module > 5. Interchange the camera board for a VGA sensor > 6. Load the appropriate sensor driver. > > All that without needing to restart the board. > > Does that really sound _that_ crazy to everyone? :) Totally :-) One good reason not to support that is that the busses used by the sensors (I2C and CCDC parallel interface) are not hot-pluggable. You can't get connect/disconnect events, you can't discover devices dynamically, and connecting/disconnected a sensor while the system is powered on might damage both the sensor and the processor. Is that a good enough reason ? :-) -- 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
