On Wednesday 14 January 2009 17:44:38 Mike Isely wrote: > On Wed, 14 Jan 2009, Mike Isely wrote: > > On Wed, 14 Jan 2009, Mauro Carvalho Chehab wrote: > > > > [...] > > > > > I can see some troubles here: > > > > > > 1) The bus info helps to identify the place where you'll find the > > > device info at sysfs; > > > > > > 2) This is a V4L2 API non-compliance. All drivers should be > > > compliant with the API; > > > > > > 3) If we all agree that bus_info doesn't matter at all and decide > > > to change V4L2 API, we'll still have a big trouble: most devices > > > don't have a serial number. > > > > > > The other patches are ok. > > > > I was asked to make this change, because otherwise there's no means > > via the V4L interface to uniquely REPEATABLY be able to identify > > the same device each time it is plugged in. I have gotten > > complaints about this. I actually pointed out that bus_info was > > about the "where" not the "what" of the device, but I was convinced > > to change this - after being surprised that the V4L spec allowed > > for this. Look at the online v4l spec; the following description > > exists about bus_info (as part of the VIDIOC_QUERYCAP description): > > [...] > > Mauro: > > If you still don't like this specific changeset, then OK, but I'd > still appreciate it if you could pull the other changes (especially > the v4l2_subdev fix). Mauro, I agree with Mike on this: please pull at least the v4l2_subdev fix which must go asap to 2.6.29 as well. It's a very embarrassing bug that I introduced and that Mike found (thanks Mike!). Regards, Hans > And I'd appreciate some suggestions from anyone about a means via the > V4L interface to make available a device-specific identifier, like a > serial number. Yes I know such a thing is not always available with > all devices, but it is available for Hauppauge devices in general and > users want to have access to that information for purposes of mapping > behavior in userspace. > > -Mike -- Hans Verkuil - video4linux developer - sponsored by TANDBERG -- 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
