On 05/07/2015 04:14 PM, Maciej W. Rozycki wrote: > On Thu, 7 May 2015, Peter Hurley wrote: > >>> What's the point of having two parameters as synonyms whose syntax is not >>> compatible to each other in the general case? I'd expect the following >>> cases to be handled: >>> >>> 1. Regular console only (no early console requested) => `console=foo...'. >>> >>> 2. Both early and regular console => `earlycon=blah... console=foo...'. >>> >>> 3. Early console handing over to regular console => `earlycon=blah...'. >> >> 4. Early console only => `earlycon=blah...' >> >> How to distinguish between 3 & 4? > > Good point. If you want to disable the handover, then it has to be > handled by the early console driver somehow. Perhaps an option for > `earlycon=' (e.g. `nohandover') would be required for that. In that case > the default selection would apply for the regular console, depending on > the available drivers. > > Your concern appears to me unrelated to `earlycon=' vs `console=' > parameter aliasing though. The same observation about the handover > applies whether the parameters are aliased to each other or not. Have I > missed anything? > >>> Why do you want to support `console=blah...' too (a question to be asked >>> back in 2007, but better late than never)? >> >> Command line is considered to be userspace, so it doesn't really matter >> what I think about whether console= should have been overloaded like that. >> >> The fact is, it was. > > The change has not been cast in stone, it can always be reverted if on > the second thoughts it is concluded to have been wrong. > > How does this overload interact with multiple `console=' options being > present BTW, which one is considered the early console? Or do we support > driving multiple early consoles in parallel just as we do with regular > consoles? Please familiarize yourself with the existing 'console=' and 'earlycon=' command line options documented in Documentation/kernel-parameters.txt These have not changed with 4.1-rc Regards, Peter Hurley -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
