[patch] serial: add parameter to force skipping the test for theTXEN bug

From: Chuck Ebbert
Date: Mon Apr 20 2009 - 18:07:54 EST


serial: add parameter to force skipping the test for the TXEN bug

Allow users to force skipping the TXEN test at init time. Applies
to all serial ports. Intended for debugging only.

Signed-off-by: Chuck Ebbert <cebbert@xxxxxxxxxx>

Index: linux-2.6.29.noarch/drivers/serial/8250.c
===================================================================
--- linux-2.6.29.noarch.orig/drivers/serial/8250.c
+++ linux-2.6.29.noarch/drivers/serial/8250.c
@@ -67,6 +67,8 @@ static int serial_index(struct uart_port
return (serial8250_reg.minor - 64) + port->line;
}

+static unsigned int skip_txen_test; /* force skip of txen test at init time */
+
/*
* Debugging.
*/
@@ -2097,7 +2099,7 @@ static int serial8250_startup(struct uar
is variable. So, let's just don't test if we receive
TX irq. This way, we'll never enable UART_BUG_TXEN.
*/
- if (up->port.flags & UPF_NO_TXEN_TEST)
+ if (skip_txen_test || up->port.flags & UPF_NO_TXEN_TEST)
goto dont_test_tx_en;

/*
@@ -3245,6 +3247,9 @@ MODULE_PARM_DESC(share_irqs, "Share IRQs
module_param(nr_uarts, uint, 0644);
MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");

+module_param(skip_txen_test, uint, 0644);
+MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
+
#ifdef CONFIG_SERIAL_8250_RSA
module_param_array(probe_rsa, ulong, &probe_rsa_count, 0444);
MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
--
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