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Revert "usb: pl2303: do not round to the next nearest standard baud rate for the divisor based baud rate encoding method"

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This reverts commit 75417d9f99.

Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip.  This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.

Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Frank Schäfer <fschaefer.oss@googlemail.com>
Acked-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2013-11-01 09:19:34 -07:00
parent 336b9daf90
commit 7e12a6fcbf
1 changed files with 30 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
drivers/usb/serial/pl2303.c
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@ -273,46 +273,44 @@ static void pl2303_encode_baudrate(struct tty_struct *tty,
struct usb_serial_port *port,
u8 buf[4])
{
const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, 3600,
4800, 7200, 9600, 14400, 19200, 28800, 38400,
57600, 115200, 230400, 460800, 500000, 614400,
921600, 1228800, 2457600, 3000000, 6000000 };
struct usb_serial *serial = port->serial;
struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
int baud;
int i;
/*
* NOTE: Only the values defined in baud_sup are supported!
* => if unsupported values are set, the PL2303 seems to use
* 9600 baud (at least my PL2303X always does)
*/
baud = tty_get_baud_rate(tty);
dev_dbg(&port->dev, "baud requested = %d\n", baud);
if (!baud)
return;
/* Set baudrate to nearest supported value */
for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
if (baud_sup[i] > baud)
break;
}
if (i == ARRAY_SIZE(baud_sup))
baud = baud_sup[i - 1];
else if (i > 0 && (baud_sup[i] - baud) > (baud - baud_sup[i - 1]))
baud = baud_sup[i - 1];
else
baud = baud_sup[i];
/* type_0, type_1 only support up to 1228800 baud */
if (spriv->type != HX)
baud = min_t(int, baud, 1228800);
if (spriv->type != HX || baud <= 115200) {
/*
* NOTE: Only the values defined in baud_sup are supported !
* => if unsupported values are set, the PL2303 seems to
* use 9600 baud (at least my PL2303X always does)
*/
const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400,
3600, 4800, 7200, 9600, 14400, 19200,
28800, 38400, 57600, 115200, 230400,
460800, 500000, 614400, 921600,
1228800, 2457600, 3000000, 6000000 };
int i;
/* Set baudrate to nearest supported value */
for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
if (baud_sup[i] > baud)
break;
}
if (i == ARRAY_SIZE(baud_sup))
baud = baud_sup[i - 1];
else if (i > 0
&& (baud_sup[i] - baud) > (baud - baud_sup[i - 1]))
baud = baud_sup[i - 1];
else
baud = baud_sup[i];
/* type_0, type_1 only support up to 1228800 baud */
if (spriv->type != HX)
baud = min_t(int, baud, 1228800);
/* Direct (standard) baud rate encoding method */
put_unaligned_le32(baud, buf);
} else {
@ -333,17 +331,10 @@ static void pl2303_encode_baudrate(struct tty_struct *tty,
* => 8 < B < 16: device seems to work not properly
* => B <= 8: device uses the max. value B = 512 instead
*/
unsigned int A, B;
/* Respect the specified baud rate limits */
baud = max_t(int, baud, 75);
if (spriv->type == HX)
baud = min_t(int, baud, 6000000);
else
baud = min_t(int, baud, 1228800);
/* Determine factors A and B */
A = 0;
B = 12000000 * 32 / baud; /* 12MHz */
unsigned int A = 0;
unsigned int B = 12000000 * 32 / baud; /* 12MHz */
B <<= 1; /* Add one bit for rounding */
while (B > (512 << 1) && A <= 14) {
A += 2;