On Tue, May 05, 2009 at 07:09:01PM +0100, Mark Brown wrote: > > I planned to use that macro a second time for the register write-back at > > resume time. But unfortunately, the i2c stack is so badly broken that it > > does not allow the write of a whole data block without having the length > > itself as part of the message (which is wrong for the codec). > > Could you clarify what you mean when you say that the I2C block requires > the length be part of the message? The I2C stack needs to know the > amount of data to write but I'm not aware of any restrictions it places > on the content of the data. All high-level i2c functions to write block data, namely i2c_smbus_write_block_data() and i2c_smbus_write_i2c_block_data(), put the length of the data being sent inside the block sent on the wire. I couldn't believe it myself, but even my hardware I2C analyzer clearly shows that. The API seems to assume that communication to I2C devices always wants data to be sent with a leading command, followed by the number of data bytes attached and then the data itself. Correct me if I'm wrong on that. Daniel _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
