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(please CC, not on the list) Hi, xscale-type UARTs have an extra bit (UUE) in the IER register that has to be written as 1 to enable the UART. At the end of autoconfig() in drivers/serial/8250.c, the IER register is unconditionally written as zero, which turns off the UART, and makes any subsequent printch() hang the box. Since other 8250-type UARTs don't have this enable bit and are thus always 'enabled' in this sense, it can't hurt to enable xscale-type serial ports all the time as well. The attached patch changes the autoconfig() exit path to see if the port has an UUE enable bit, and if yes, to write UUE=1 instead of just putting a zero into IER, using the same test as is used at the beginning of serial8250_console_write(). cheers, Lennert Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> diff -urN linux-2.6.13.orig/drivers/serial/8250.c linux-2.6.13/drivers/serial/8250.c --- linux-2.6.13.orig/drivers/serial/8250.c 2005-08-29 01:41:01.000000000 +0200 +++ linux-2.6.13/drivers/serial/8250.c 2005-10-02 21:38:51.000000000 +0200 @@ -936,7 +936,10 @@ serial_outp(up, UART_MCR, save_mcr); serial8250_clear_fifos(up); (void)serial_in(up, UART_RX); - serial_outp(up, UART_IER, 0); + if (up->capabilities & UART_CAP_UUE) + serial_outp(up, UART_IER, UART_IER_UUE); + else + serial_outp(up, UART_IER, 0); out: spin_unlock_irqrestore(&up->port.lock, flags); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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