On Fri, Apr 29, 2016 at 05:02:57PM +0100, Richard W.M. Jones wrote: > On Fri, Apr 29, 2016 at 08:54:13AM -0700, Greg KH wrote: > > You are trying to take a generalized kernel and somehow "know" about the > > hardware ahead of time it is going to run on. That seems like two > > conflicting requirements, don't you agree? > > We would have the 8250 serial port in any kernel. Even if Fedora > kernel maintainers allowed us to have specialized kernels for each > purpose, I would use the simple ISA serial port here because it allows > us to capture debug messages very early in the boot. Alternatives > like virtio-console don't allow that. > > The kernel does know what hardware it's running on - via the CPUID > hypervisor leaf. It's also possible for us to tell the kernel about > the hardware using the command line, ACPI[*], DT, etc. I'd really > like to tell the kernel this is a 16550A, not broken, you don't need > to spend time testing that.
Then properly describe the device to the kernel in a way that you know you don't have to do the 20ms sleep from your system configuration file (acpi, dt, etc.) good luck, greg k-h
