This whole area with HDMI seems to be a mess. The Sony box when it was connected to our old JVC TV would auto switch with HDMI but connected to the LG TV it wont by HDMI but will via Scart. Also the cables come into this as I'm not sure all HDMI cables are equal.
Stuart
HDMI auto-switching only works if both devices support CEC (Consumer Electronics Control)
or your TV/monitor auto-detects a video signal on the HDMI port (usually only on HDMI1 if so). SCART works by pulling pin 8 high (9.5-12v) to switch to the appropriate socket. This does depend on the SCART lead having pin 8 connected at both ends though. With HDMI, CEC wiring is mandatory, although implementation of the protocol (which is a single wire bi-directional bus) is not.
Sooo, all HDMI leads
must include CEC wiring although one or other of your devices may not implement it, whereas (AFAIK) all SCART equipped devices
must support switching on pin 8 although many cheap SCART leads are not wired with pin 8 connected.
Much more interesting (to me anyway
) is that I can turn my sky box over with my PC, now that it is network connected, and have been terribly geeky and written a script so that the wife never misses a soap again.