On Sun, 7 Jun 2009, Roger wrote: > >From looking at "linux/drivers/media/dvb/frontends/s5h1411.c", The > s5h1411_readreg wants to see "2" but is getting "-5" from the i2c bus. > > --- Snip --- > > s5h1411_readreg: readreg error (ret == -5) > pvrusb2: unregistering DVB devices > device: 'dvb0.net0': device_unregister > > --- Snip --- > > What exactly does this mean? Roger: It means that the module attempted an I2C transfer and the transfer failed. The I2C adapter within the pvrusb2 driver will return either the number of bytes that it transferred or a failure code. The failure code, as is normal convention in the kernel, will be a negated errno value. Thus the expected value of 2 would be the fact that it probably tried a 2 byte transfer, while the actual value returned of -5 indicate an EIO error, which is what the pvrusb2 driver will return when the underlying I2C transaction has failed. Of course the real question is not that it failed but why it failed. And for that I unfortunately do not have an answer. It's possible that the s5h1411 driver did something that the chip didn't like and the chip responded by going deaf on the I2C bus. More than a few I2C-driven parts can behave this way. It's also possible that the part might have been busy and unable to respond - but usually in that case the driver for such a part will be written with this in mind and will know how / when to communicate with the hardware. -Mike -- Mike Isely isely @ isely (dot) net PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8 -- 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
