On Wed 2018-06-20 15:37:47, Hans de Goede wrote: > Hi, > > On 20-06-18 13:03, Petr Mladek wrote: > > On Tue 2018-06-19 13:57:26, Hans de Goede wrote: > > > The goal of passing the "quiet" option to the kernel is for the kernel > > > to be quiet unless something really is wrong. > > > > > > Sofar passing quiet has been (mostly) equivalent to passing > > > loglevel=4 on the kernel commandline. Which means to show any messages > > > with a level of KERN_ERR or higher severity on the console. > > > > > > In practice this often does not result in a quiet boot though, since > > > there are many false-positive or otherwise harmless error messages > > > printed, > > > defeating the purpose of the quiet option. Esp. the ACPICA code is really > > > bad wrt this, but there are plenty of others too. > > > > I see your pain. But this sounds like a workaround for a broken code. > > This change might just encourage people to create even more mess. > > I've been submitting patches upstream to fix false-positive KERN_ERR > messages for more then a year now and getting a KERN_ERR free kernel > (on more then 1 specific model hw) is just undoable. Every release some > new nonsense error comes up, like e.g.: > > https://bugzilla.redhat.com/show_bug.cgi?id=1568276 > > Besides this random KERN_ERR cases (of which there are plenty > by themselves) I've also had long discussions with the ACPICA upstream > maintainers, but they refuse to change this instead insisting that: > > a) Vendors should fix there DSDTs to be perfect; and > b) end-users should then update their BIOS to fix this > > Neither of which is a realistic expectation in anyway.
Thanks for the many examples. It would help me to argue if anyone later complains about this change ;-) > > > This commit makes CONSOLE_LOGLEVEL_QUIET configurable. > > > > > > This for example will allow distros which want quiet to really mean quiet > > > to set CONSOLE_LOGLEVEL_QUIET so that only messages with a higher severity > > > then KERN_ERR (CRIT, ALERT, EMERG) get printed, avoiding an endless game > > > of whack-a-mole silencing harmless error messages. > > > > I find it a bit confusing that "quiet" would mean something different > > on different systems. > > The kernel is so configurable already that I don't think this really is much > of an issue, quiet will still mean quiet on all systems, some might just > be a tad more quiet (or actually be quiet) compared to others. Just for record. Some people actually do a lot to prevent adding new configure options. The many possibilities cause troubles to users and even experienced developers. A common argument against adding new options is: "How users could be able to choose reasonable value when even experts (maintainers, developers) are not able to agree on it". > I went with making this configurable because I expect that to > be a controversial change. Exactly, I thought about changing the default. But it might just bring a lot of bike-shedding. I do not see any other good option. More people like this patch. So I pushed it into printk.git, branch for-4.19. Best Regards, Petr
