Re: [omap3camera] How does a lens subdevice get powered up?
Hi Sergio, On Wednesday 25 August 2010 22:15:36 Aguirre, Sergio wrote: Hi Laurent, I see that usually a sensor is powered up on attempting a VIDIOC_STREAMON at the capture endpoint of the pipeline, in which the sensor is linked. Now, what I don't understand quite well is, the Lens driver is a separate subdevice, BUT it's obviously not linked to the sensor, nor the pipeline. How would the lens driver know when to power up? At the moment a userspace application needs to keep the lens subdev open to power-up the lens controller. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [omap3camera] How does a lens subdevice get powered up?
Hi Laurent, -Original Message- From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com] Sent: Thursday, August 26, 2010 2:31 AM To: Aguirre, Sergio Cc: linux-media@vger.kernel.org; Nataraju, Kiran Subject: Re: [omap3camera] How does a lens subdevice get powered up? Hi Sergio, On Wednesday 25 August 2010 22:15:36 Aguirre, Sergio wrote: Hi Laurent, I see that usually a sensor is powered up on attempting a VIDIOC_STREAMON at the capture endpoint of the pipeline, in which the sensor is linked. Now, what I don't understand quite well is, the Lens driver is a separate subdevice, BUT it's obviously not linked to the sensor, nor the pipeline. How would the lens driver know when to power up? At the moment a userspace application needs to keep the lens subdev open to power-up the lens controller. I see... So in that case, does it make sense to consider it as a media entity? I mean, there's no link, nor pad operations involved, so it doesn't really add any value... What do you think? Regards, Sergio -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [omap3camera] How does a lens subdevice get powered up?
Hi Sergio, On Thursday 26 August 2010 16:54:37 Aguirre, Sergio wrote: On Thursday, August 26, 2010 2:31 AM Laurent Pinchart wrote: On Wednesday 25 August 2010 22:15:36 Aguirre, Sergio wrote: I see that usually a sensor is powered up on attempting a VIDIOC_STREAMON at the capture endpoint of the pipeline, in which the sensor is linked. Now, what I don't understand quite well is, the Lens driver is a separate subdevice, BUT it's obviously not linked to the sensor, nor the pipeline. How would the lens driver know when to power up? At the moment a userspace application needs to keep the lens subdev open to power-up the lens controller. I see... So in that case, does it make sense to consider it as a media entity? I mean, there's no link, nor pad operations involved, so it doesn't really add any value... What do you think? Even if not part of the image pipeline, the lens controller is still part of the media device. I think it makes sense to expose it as an entity and a V4L2 subdevice. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [omap3camera] How does a lens subdevice get powered up?
Hi Laurent, -Original Message- From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com] Sent: Thursday, August 26, 2010 10:04 AM To: Aguirre, Sergio Cc: linux-media@vger.kernel.org; Nataraju, Kiran Subject: Re: [omap3camera] How does a lens subdevice get powered up? Hi Sergio, On Thursday 26 August 2010 16:54:37 Aguirre, Sergio wrote: On Thursday, August 26, 2010 2:31 AM Laurent Pinchart wrote: On Wednesday 25 August 2010 22:15:36 Aguirre, Sergio wrote: I see that usually a sensor is powered up on attempting a VIDIOC_STREAMON at the capture endpoint of the pipeline, in which the sensor is linked. Now, what I don't understand quite well is, the Lens driver is a separate subdevice, BUT it's obviously not linked to the sensor, nor the pipeline. How would the lens driver know when to power up? At the moment a userspace application needs to keep the lens subdev open to power-up the lens controller. I see... So in that case, does it make sense to consider it as a media entity? I mean, there's no link, nor pad operations involved, so it doesn't really add any value... What do you think? Even if not part of the image pipeline, the lens controller is still part of the media device. I think it makes sense to expose it as an entity and a V4L2 subdevice. Hmm... I don't know what I was thinking... you're right. :) Now that I rethink what I just said vs your answer, I think you have a point, so I'll drop that thought... However, I think still there's something that could be done here... Imagine a scenario in which you have 2 sensors, each one with a different Coil motor driver to control each sensor's lens position. Should we have a way to register some sort of association between Sensor and lens subdevices? That way, by querying the media device, an app can know which lens is associated with what sensor, without any hardcoding. That would be very similar to the case in which you would want to associate an audio capturing subdev with a video capturing subdev. They are not technically sharing the same data, but they are related. Is this kind of association considered in the Media Controller framework implementation currently? Regards, Sergio -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [omap3camera] How does a lens subdevice get powered up?
Hi Sergio, On Thursday 26 August 2010 17:33:28 Aguirre, Sergio wrote: On Thursday, August 26, 2010 10:04 AM Laurent Pinchart wrote: Even if not part of the image pipeline, the lens controller is still part of the media device. I think it makes sense to expose it as an entity and a V4L2 subdevice. Hmm... I don't know what I was thinking... you're right. :) Now that I rethink what I just said vs your answer, I think you have a point, so I'll drop that thought... However, I think still there's something that could be done here... Imagine a scenario in which you have 2 sensors, each one with a different Coil motor driver to control each sensor's lens position. Should we have a way to register some sort of association between Sensor and lens subdevices? That way, by querying the media device, an app can know which lens is associated with what sensor, without any hardcoding. That would be very similar to the case in which you would want to associate an audio capturing subdev with a video capturing subdev. They are not technically sharing the same data, but they are related. Is this kind of association considered in the Media Controller framework implementation currently? It's implemented in the latest media controller RFC :-) Entities now have a group ID that the driver can set to report associations such as sensor-coil-flash or video-audio. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [omap3camera] How does a lens subdevice get powered up?
Hi Laurent, -Original Message- From: Laurent Pinchart [mailto:laurent.pinch...@ideasonboard.com] Sent: Thursday, August 26, 2010 10:36 AM To: Aguirre, Sergio Cc: linux-media@vger.kernel.org; Nataraju, Kiran Subject: Re: [omap3camera] How does a lens subdevice get powered up? Hi Sergio, On Thursday 26 August 2010 17:33:28 Aguirre, Sergio wrote: On Thursday, August 26, 2010 10:04 AM Laurent Pinchart wrote: Even if not part of the image pipeline, the lens controller is still part of the media device. I think it makes sense to expose it as an entity and a V4L2 subdevice. Hmm... I don't know what I was thinking... you're right. :) Now that I rethink what I just said vs your answer, I think you have a point, so I'll drop that thought... However, I think still there's something that could be done here... Imagine a scenario in which you have 2 sensors, each one with a different Coil motor driver to control each sensor's lens position. Should we have a way to register some sort of association between Sensor and lens subdevices? That way, by querying the media device, an app can know which lens is associated with what sensor, without any hardcoding. That would be very similar to the case in which you would want to associate an audio capturing subdev with a video capturing subdev. They are not technically sharing the same data, but they are related. Is this kind of association considered in the Media Controller framework implementation currently? It's implemented in the latest media controller RFC :-) Entities now have a group ID that the driver can set to report associations such as sensor-coil-flash or video-audio. Oh ok, I see. Perfect! Thanks for clarifying that. Regards, Sergio -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[RESEND][omap3camera] How does a lens subdevice get powered up?
(Resending as plain text, as I sent it originally as HTML and got rejected by ML security policies) Hi Laurent, I see that usually a sensor is powered up on attempting a VIDIOC_STREAMON at the capture endpoint of the pipeline, in which the sensor is linked. Now, what I don't understand quite well is, the Lens driver is a separate subdevice, BUT it's obviously not linked to the sensor, nor the pipeline. How would the lens driver know when to power up? Regards, Sergio -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
