@@ -141,6 +141,8 @@ struct pl2303_private {
spinlock_t lock;
u8 line_control;
u8 line_status;
+
+ u8 line_settings[7];
};
static int pl2303_vendor_read(__u16 value, __u16 index,
@@ -280,10 +282,6 @@ static void pl2303_set_termios(struct tty_struct *tty,
int baud_floor, baud_ceil;
int k;
- /* The PL2303 is reported to lose bytes if you change
- serial settings even to the same values as before. Thus
- we actually need to filter in this specific case */
-
if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
return;
@@ -420,10 +418,29 @@ static void pl2303_set_termios(struct tty_struct *tty,
dev_dbg(&port->dev, "parity = none\n");
}
- i = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
- SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
- 0, 0, buf, 7, 100);
- dev_dbg(&port->dev, "0x21:0x20:0:0 %d\n", i);
+ /*
+ * Some PL2303 are known to lose bytes if you change serial settings
+ * even to the same values as before. Thus we actually need to filter
+ * in this specific case.
+ *
+ * Note that the tty_termios_hw_change check above is not sufficient
+ * as a previously requested baud rate may differ from the one
+ * actually used (and stored in old_termios).
+ *
+ * NOTE: No additional locking needed for line_settings as it is
+ * only used in set_termios, which is serialised against itself.
+ */
+ if (!old_termios || memcmp(buf, priv->line_settings, 7)) {
+ i = usb_control_msg(serial->dev,
+ usb_sndctrlpipe(serial->dev, 0),
+ SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
+ 0, 0, buf, 7, 100);
+
+ dev_dbg(&port->dev, "0x21:0x20:0:0 %d\n", i);
+
+ if (i == 7)
+ memcpy(priv->line_settings, buf, 7);
+ }
/* change control lines if we are switching to or from B0 */
spin_lock_irqsave(&priv->lock, flags);
This is a note to let you know that I have just added a patch titled USB: pl2303: fix data corruption on termios updates to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.11.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 10f44240b685093af670e42de1a069465266b422 Mon Sep 17 00:00:00 2001 From: Johan Hovold <jhovold@gmail.com> Date: Sun, 29 Dec 2013 19:22:53 +0100 Subject: USB: pl2303: fix data corruption on termios updates MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 623c8263376c0b8a4b0c220232e7313d762cd0cc upstream. Some PL2303 devices are known to lose bytes if you change serial settings even to the same values as before. Avoid this by comparing the encoded settings with the previsouly used ones before configuring the device. The common case was fixed by commit bf5e5834bffc6 ("pl2303: Fix mode switching regression"), but this problem was still possible to trigger, for instance, by using the TCSETS2-interface to repeatedly request 115201 baud, which gets mapped to 115200 and thus always triggers a settings update. Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/usb/serial/pl2303.c | 33 +++++++++++++++++++++++++-------- 1 file changed, 25 insertions(+), 8 deletions(-) -- 1.8.3.2