On Mon, 2005-08-15 at 15:52 +0100, Russell King wrote: > On Mon, Aug 15, 2005 at 09:10:56AM -0500, V. Ananda Krishnan wrote: > > The problem described here is related to the 8250_pci driver in > > 2.6.12.3/2.6.12.4 kernels. When 8250_pci device driver detects a serial > > port pci device and sets up the default setup (8250_pci.c), it tries to > > find a match or unused port (serial8250_find_match_or_unused proc in in > > 8250.c). > > > > This leads to the uart_match_port with one of the parameters as > > serial8250_ports[i].port. During debugging, I noticed that the none of > > elements of the serial8250_ports[i].port.type was having any port value. > > Every variable has a value. In this case, they start off as PORT_UNKNOWN > as expected. > > > So the serial8250_register_port fails and the device driver module fails > > to load. > > I don't follow you here - failure of this function is not dependent on > port.type being PORT_UNKNOWN.
Sorry for not being clear. When 8250_pci.c invokes the function serial8250_register_port(&serial_port) at line 1736 (linux-2.6.12.4), I am seeing the following values: number of ports in the pci device is 1, and the port structure has io_type:2, iobase:0, membase:80005000 and mapbase:d6000000. In turn, The serial8250_register_port procedure in 8250.c calls the serial8250_find_match_or_unused(port) routine (line 2439 in 8250.c of linux-2.6.12.4) which returns 0. Hence the uart_add_one_port(&serial8250_reg, &uart->port) (line 2455 in 8250.c of linux-2.6.12.4) codes are not touched and serial8250_register_port returns -28 (-ENOSPC) to the register_port caller. Please let me know, if this is data is not clear and thanks for your immediate attention. > > > In this scenario, the last resort to find any entry which > > doesn't have a real port associated with it also fails, because of the > > null value in the serial8250_ports[i].port.type. > > Again I don't follow you here. > > The only reason serial8250_find_match_or_unused() will return NULL is > if all registered port entries correspond with real hardware ports. > In that case, the solution is to increase the number of 8250 ports > via the kernels configuration. > > > I would like to know when the port.type values in uart_8250_port structure > > (in serial8250_ports[i]) is populated? Is there anything missing in the > > serial8250_find_match_or_unused codes? Any help to degug this problem > > is appreciated. Thanks. > > They're set to something other than PORT_UNKNOWN when a port is > discovered via serial8250_register_port() / uart_add_one_port(). > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
