On Sun, 22 Feb 2009, Hans de Goede wrote: > Yes that is what we are talking about, the camera having a gravity switch > (usually nothing as advanced as a gyroscope). Also the bits we are talking > about are in a struct which communicates information one way, from the camera > to userspace, so there is no way to clear the bits to make the camera do something. First, I'd like to say I agree with most that the installed orientation of the camera sensor really is a different concept than the current value of a gravity sensor. It's not necessary, and maybe not even desirable, to handle them in the same way. I do not see the advantage of using reserved bits instead of controls. The are a limited number of reserved bits. In some structures there are only a few left. They will run out. Then what? Packing non-standard sensor attributes and camera sensor meta-data into a few reserved bits is not a sustainable policy. Controls on the other card are not limited and won't run out. Currently reserved bits and previously reserved but now in use bits look exactly the same. How does an app know if the bits are valid or not? More reserved bits? The control API is already designed to allow for enumeration of controls. Reserved bits have no meta-data to document them. An app sees that some bits in the input struct which were reserved when it was written are now set. What does this tell the app? Nothing. What can the app tell the user? Nothing. The control API provides for control meta-data. We have a means of enumeration, name, min, max, step size, and various flags to tell us about a control that wasn't already handled. Does this new gravity sensor have 45 degree resolution? The control's step size can show this even if only 90 degree rotations had been considered when gravity sensor support was first added to some other driver. At the very least, the app (and various existing utilities) can provide information about the controls to the user. -- 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
