I have a NEC Versa 2780MT laptop with an internal plug and play
modem. In older kernels, I had to use isapnp and then
setserial /dev/ttyS1 uart 16550
to get the modem to work. When I installed kernel 2.1.105, any
setserial command to this port gave "invalid argument". A quick check
at the serial driver sources and a run of setserial through the
debugger indicated that this was happening because the xmit_fifo_size
was set to zero. Apparently, this field was not used in older
kernels. In any case, I made a patch to setserial that allows me to
set this value and enables setserial to give its value when run with
the -a flag. Without this patch, I am unable to use my modem, but
with the patch, everything works fine.
Please let me know whether this or an equivalent patch will be
included in a new version of setserial. If so, then the
Documentation/Changes file distributed with the kernel should indicate
that this version of setserial is required with newer kernels.
Thanks!
-- E. Jay Berkenbilt (ejb@ql.org) | http://www.ql.org/q/===========================================================================
--- setserial.c.qdist Tue Jun 9 09:35:11 1998 +++ setserial.c Fri Sep 18 09:02:23 1998 @@ -66,6 +66,7 @@ #define CMD_CONFIG 10 #define CMD_GETMULTI 11 #define CMD_SETMULTI 12 +#define CMD_XMIT_FIFO 13 #define FLAG_CAN_INVERT 0x0001 #define FLAG_NEED_ARG 0x0002 @@ -111,6 +112,7 @@ CMD_CONFIG, "autoconfig", 0, 0, 0, 0, CMD_GETMULTI, "get_multiport",0, 0, 0, 0, CMD_SETMULTI, "set_multiport",0, 0, 0, 0, + CMD_XMIT_FIFO, "xmit_fifo", 0, 0, 0, FLAG_NEED_ARG, 0, 0, 0, 0, 0, 0, }; @@ -330,6 +332,8 @@ printf("\tBaud_base: %d, close_delay: %d, divisor: %d\n", serinfo.baud_base, serinfo.close_delay, serinfo.custom_divisor); + printf("\tTransmit fifo size: %d\n", + serinfo.xmit_fifo_size); #ifdef ASYNC_CLOSING_WAIT_NONE if (serinfo.closing_wait == ASYNC_CLOSING_WAIT_INF) strcpy(buf1, "infinte"); @@ -485,6 +489,9 @@ set_multiport(device, fd, &arg); break; + case CMD_XMIT_FIFO: + new_serinfo.xmit_fifo_size = atonum(*arg++); + break; default: fprintf(stderr, "Internal error: unhandled cmd #%d\n", p->cmd); exit(1); @@ -586,6 +593,7 @@ fprintf(stderr, "\t spd_cust\tuse the custom divisor to set the speed at 38.4kb\n"); fprintf(stderr, "\t\t\t\t(baud rate = baud_base / custom_divisor)\n"); fprintf(stderr, "\t spd_normal\tuse 38.4kb when a buad rate of 38.4kb is selected\n"); + fprintf(stderr, "\t xmit_fifo\tset the transmit fifo size\n"); fprintf(stderr, "\n"); fprintf(stderr, "Use a leading '0x' for hex numbers.\n"); fprintf(stderr, "CAUTION: Using an invalid port can lock up your machine!\n");
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