On Fri, 07 Sep 2012 15:58:22 +0200, Michael Lawnick wrote: > I did not test yet, but thought already in same direction. The draw back > of this is that there is still maximum tree depth, but we could say 8 > should be enough and the performance issue. May be introducing the depth > into struct i2c_adapter and setting it to parent->depth + 1?
I think we are safe with max depth 8 (actually 7.) I still have to see a setup with depth > 1, and I seriously don't expect ever seeing one with depth > 3. As far as performance is concerned, I thought about storing the depth value in struct i2c_adapter, but in fact I suspect the call to i2c_adapter_depth(adap) will be dropped at compilation time if CONFIG_PROVE_LOCKING isn't set, so the overhead should be zero. While a small overhead will be present if we store the value (the compiler won't be able to optimize that away.) I couldn't find the time to check this, though, which is why my original reply is still in my draft folder. -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
