On Mon, Nov 10, 2014 at 07:05:14AM -0800, Kevin Cernekee wrote: > On Mon, Nov 10, 2014 at 6:25 AM, Rob Herring <robh@xxxxxxxxxx> wrote: > > On Sun, Nov 9, 2014 at 2:55 AM, Kevin Cernekee <cernekee@xxxxxxxxx> wrote: > >> By default, bcm63xx_uart.c uses the standard 8250 device naming and > >> major/minor numbers. There are at least two situations where this could > >> be a problem: > >> > >> 1) Multiplatform kernels that need to support some chips that have 8250 > >> UARTs and other chips that have bcm63xx UARTs. > >> > >> 2) Some older chips like BCM7125 have a mix of both UART types. > >> > >> Add a new Kconfig option to tell the driver whether to register itself > >> as ttyS or ttyBCM. By default it will retain the existing "ttyS" > >> behavior to avoid surprises. > > > > While I understand the desire to have stable names, this is the > > opposite direction we want to go. Per platform tty names complicates > > having a generic userspace. It is not so bad since most ARM platforms > > use ttyS or ttyAMA, but just think what the kernel and userspace side > > would look like if every single platform did this. We can't change > > everything to ttyS because the other names are already an ABI. > > > > This can be solved with a udev rule to create sym links. > > Is it safe to register two console drivers named "ttyS" with the same > major/minor numbers? Not at all, think about what you are asking for here. Is the kernel allowed to register two block devices with the same major/minor numbers? greg k-h
