From 7e12a6fcbf266eb0d5b19761f91b2964ad18e371 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Fri, 1 Nov 2013 09:19:34 -0700
Subject: [PATCH] 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 75417d9f99f89ab241de69d7db15af5842b488c4.
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>
---
drivers/usb/serial/pl2303.c | 65 ++++++++++++++++---------------------
1 file changed, 28 insertions(+), 37 deletions(-)
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 04390dff926a..b93b3b30dec5 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -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;
- 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;
- }
+ /* 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];
+ 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);
+ /* 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) {
/* 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;
--
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