uart_get_divisor picks better quot

I have a case where uartclk is 33000000 and baud is 115200. The quotient is about 17.9, but the current code selects 17 as the quot. With 17 I'm getting corrupted characters transmitted. Using 18 fixes the problem. Perhaps rounding would be a better choice than truncation. -roger

===== drivers/serial/serial_core.c 1.87 vs edited =====

@@ -403,7 +403,7 @@
        if (baud == 38400 && (port->flags & UPF_SPD_MASK) ==

UPF_SPD_CUST)

                quot = port->custom_divisor;
        else

- quot = port->uartclk / (16 * baud);
+ quot = (port->uartclk + (8 * baud)) / (16 * baud);

        return quot;

}

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does linux kernel have a framework for autobaud rate and uart as dce mode.
If yes then pls tell me the interface

Manish

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of roger blofeld
Sent: Thursday, September 16, 2004 5:53 AM
To: [email protected]
Cc: [email protected]
Subject: [PATCH] uart_get_divisor picks better quot

I have a case where uartclk is 33000000 and baud is 115200. The quotient is about 17.9, but the current code selects 17 as the quot. With 17 I'm getting corrupted characters transmitted. Using 18 fixes the problem. Perhaps rounding would be a better choice than truncation. -roger

===== drivers/serial/serial_core.c 1.87 vs edited =====

@@ -403,7 +403,7 @@
        if (baud == 38400 && (port->flags & UPF_SPD_MASK) ==

UPF_SPD_CUST)

                quot = port->custom_divisor;
        else

- quot = port->uartclk / (16 * baud);
+ quot = (port->uartclk + (8 * baud)) / (16 * baud);

        return quot;

}

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