On 02/06/2014 04:29 PM, Greg Kroah-Hartman wrote: > On Thu, Feb 06, 2014 at 03:27:43PM +0100, Hannes Reinecke wrote: >> The 'active' sysfs attribute should refer to the currently >> active tty devices the console is running on, not the currently >> active console. > > That's not what Documentation/ABI/sysfs-tty says: > Shows the list of currently configured > > console devices, like 'tty1 ttyS0'. > > The last entry in the file is the active > > device connected to /dev/console. > > The file supports poll() to detect virtual > > console switches. > The problem is indeed with 'console devices'. There is no such thing; you only have tty devices where the console is running on.
>> The console structure doesn't refer to any device in sysfs, >> only the tty the console is running on has. > > That sentance doesn't make sense. > >> So we need to print out the tty names in 'active', not >> the console names. > > But that doesn't match the documentation. > > What exactly are you trying to "fix" here? What is the problem that the > current file has that is broken? And as you are changing what this file > means, what will break if the information in the file changes? > systemd is using the 'active' sysfs attribute to figure out on which _tty_ device to start a getty on. As soon as the console name and the tty name are different you have no means of figuring out which _device_ to open. AFAICS the console 'device' (ie the current entry in 'active') doesn't have _any_ equivalent in sysfs; it just so happens that for most console drivers the tty driver name is identical. But this is not a requirement, and fails for drivers which have a different device for the console and the tty. EG on S/390 the 3270 tty has the devices /dev/3270/tty1 but the console driver announces the name 'tty3270'. So as per current rules the 'active' attribute contains tty32700 which correct as per documentation, but doesn't have _any_ equivalent in sysfs. Martin has the grubby details here. But of course, the documentation should be updated to match the new behavior. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage h...@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
