On Wed, 2017-08-30 at 19:50 +0800, huibin.hong@xxxxxxxxxxxxxx wrote: > On 2017-08-30 at 19:26 Andy > Shevchenko<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > >On Wed, 2017-08-30 at 14:23 +0800, huibin.hong@xxxxxxxxxxxxxx wrote: > >> Hello everyone > >> Many RK socs have 5 uart, and our customer may use more than 4 > >> uarts, but they don't know why > >> there is not ttyS4, because we need to modify the follow config. Wh > y > >> limit the number 4? > > > >Where did you get this configuration? > > > >Moreover, 8250 module supports overriding of NR_UARTS at runtime. > > > I got the configuration from linux mainline. As I know only nr_uarts > can be changed > at runtime, UART_NR is invariant. If we want to use 5 uarts, we have > to modify UART_NR, right? > In one word, the user must change something, if he want to use more > than 5 uarts. Right, you need to define a maximum supported number of UARTs via SERIAL_8250_NR_UARTS option. The question you asked initially should be addressed to maintainer(s) of that particular file in mainline kernel. (x86 AFAIR uses 32 there) > >> config SERIAL_8250_NR_UARTS > >> int "Maximum number of 8250/16550 serial ports" > >> > >> config SERIAL_8250_RUNTIME_UARTS > >> int "Number of 8250/16550 serial ports to register at runti > me" > >> range 0 SERIAL_8250_NR_UARTS > >> default "4" -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
