> It's been a long while since I've touched EM28xx stuff, but if I > remember correctly there should be an EEPROM byte which identifies the > demodulator used. There's some EEPROM hashing code in the driver but > it's only used for devices with generic (non-manufacturer > specific/default) USB IDs. You would probably need to see the eeprom dump from both devices to see if they are actually different. Some vendors actually have a field in the eeprom which indicates what demodulator and tuner model is present (Hauppauge does this), but there are other strategies I've seen used such as: - having a GPIO input which acts as a strapping option (i.e. a resistor gets populated which indicates a different tuner/demod, and hence you have to read the GPIO value to know which board revision it is). - relying on info stored in the eeprom (see above) - having the driver probe for one of the demodulators, and if the probing fails falling back and probing for the other demod. In some cases it's just working off the I2C address, in other cases it probes specific registers for values like a chip ID. You would probably have to have both board revisions in your possession so you could do some comparison. Alternatively if you know two people who have the boards you could potentially get a USB trace under Windows and determine the heuristic used based on the traffic. For those of you who might be asking, "Why the hell didn't the manufacturer just give the new board a different USB ID?", unfortunately the answer tends to be because they wanted to quietly change the hardware design without having to go through a second round of WHQL certification. Devin -- Devin J. Heitmueller - Kernel Labs http://www.kernellabs.com -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
