Em 27-10-2010 13:48, Devin Heitmueller escreveu: > On Wed, Oct 27, 2010 at 11:41 AM, Mauro Carvalho Chehab > > Have you looked at the code for how the Conexant guys got the xc5000 > firmware load to work (which uses 64 bytes at a time). I suspect what > *really* needs to happen is that needs to be made generic so that the > stop bit is properly set (which would allow a single i2c transaction > to span across multiple USB control messages). > > Note that the xc5000 hack is actually two changes merged together - > one uses a GPIO mode in certain cases to handle clock stretching > properly (which probably has to stay there for now), and the other > allows for larger i2c transactions. I am referring to the latter > change. > > If we fix the cx231xx i2c master, then we can go back to the original > 18271 config, which avoids the risk of regression for other devices. The original code is broken, as it doesn't properly honour a max size of 8. Even if we do some optimization at cx231xx, we still need to fix the tda18271 code, as it is trying to use more than 8 bytes on some writes. Also, as you noticed, the way cx231xx sends large firmwares to xc5000 is a hack: it requires to identify that the I2C device is a xc5000 and do an special treatment for it. We may actually move all those small_i2c logic to the bridge drivers, adding those hacks inside the I2C adapter part, but this means that they'll need to have some complex-logic that are dependent on what device is connected to it, damaging the benefits that the I2C bus abstraction brings. Instead of polluting bridge drivers with I2C-device specific code, the proper way seems to use parameters to adjust the maximum size, eventually flagging the broken messages in a way that the I2C adapter won't sent a stop transaction in the middle of a larger initialization like this one. Cheers, Mauro -- 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
