From 92dfe410880b8bde731ca1a6e7da2dd3b13404e6 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 1 Nov 2013 09:18:47 -0700 Subject: [PATCH] Revert "usb: pl2303: increase the allowed baud rate range for the divisor based encoding method" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reverts commit b5c16c6a031c52cc4b7dda6c3de46462fbc92eab. 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 Cc: Frank Schäfer Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/pl2303.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c index 61c9f9d28ee9..693ed7e4871a 100644 --- a/drivers/usb/serial/pl2303.c +++ b/drivers/usb/serial/pl2303.c @@ -324,20 +324,12 @@ static int pl2303_baudrate_encode_divisor(int baud, enum pl2303_type type, */ unsigned int A, B; - /* - * NOTE: The Windows driver allows maximum baud rates of 110% of the - * specified maximium value. - * Quick tests with early (2004) HX (rev. A) chips suggest, that even - * higher baud rates (up to the maximum of 24M baud !) are working fine, - * but that should really be tested carefully in "real life" scenarios - * before removing the upper limit completely. - * Baud rates smaller than the specified 75 baud are definitely working - * fine. - */ + /* Respect the specified baud rate limits */ + baud = max_t(int, baud, 75); if (type == HX) - baud = min_t(int, baud, 6000000 * 1.1); + baud = min_t(int, baud, 6000000); else - baud = min_t(int, baud, 1228800 * 1.1); + baud = min_t(int, baud, 1228800); /* Determine factors A and B */ A = 0; B = 12000000 * 32 / baud; /* 12MHz */