On Fri, Dec 07, 2018 at 12:32:45PM +0100, Thierry Reding wrote: > Greg, > > any ideas on how we can move forward here? For reasons given elsewhere > in this thread I understand that there is no way to make the console > code run in non-atomic context. Have you ever run into a case where the > console driver couldn't busy-loop? Were there any solutions to this? I don't know of any such cases, hardware sucks at times, and we just have to deal with getting it to work by doing stuff like this :( > I've looked through quite a few drivers and they all end up with a busy > loop, waiting for the transmission FIFO to become empty. There are also > a few implementations for hypervisors that call back into some firmware > in order to send the characters, but I expect those to do the busy > looping in the firmware. busy loops are ok here, as you point out. > Perhaps the most prominent case that I came across and that is quite > similar to this discussion is netconsole. There's a lot of code in the > network layer that exists only to allow using a network device for > outputting a console. I don't think the changes to the mailbox > framework are anywhere near as complicated. Neither do I, I have no objection to your changes at all. thanks, greg k-h
