Am 01.11.2013 13:19, schrieb Mika Westerberg:
> On Fri, Nov 01, 2013 at 12:49:22PM +0100, Frank Schäfer wrote:
>> Some PL2303 chips are reported to lose bytes if the serial settings are set to
>> the same values as before.
>> At least HXD chips are affected, HX chips seem to be ok.
>> The current code tries to avoid this by calling tty_termios_hw_change(), but
>> this check isn't sufficient because different requested baud rates can result
>> in identic encoded baud rates.
>> The solution is to save and compare the encoded settings instead.
> I tried this on top of rc7 and I can still see data get corrupted (both
> 115200 and 460800 bps).
Ok... Ready for the next round ? ;)
Attached are two further experimental patches.
Regards,
Frank
>From 95a3f0e0751dad4ae39fdd7a915a2fa22997a540 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Frank=20Sch=C3=A4fer?= <fschaefer.oss@xxxxxxxxxxxxxx>
Date: Fri, 1 Nov 2013 13:56:53 +0100
Subject: [PATCH] EXPERIMENTAL PATCH 1
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx>
---
drivers/usb/serial/pl2303.c | 30 ++++++++++++++++++------------
1 Datei geändert, 18 Zeilen hinzugefügt(+), 12 Zeilen entfernt(-)
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index bedf8e4..8496eef 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -496,20 +496,13 @@ static void pl2303_set_termios(struct tty_struct *tty,
struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
struct pl2303_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
- unsigned char *buf;
+ unsigned char *buf, *buf_old;
int i;
u8 control;
- /*
- * 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;
-
buf = kzalloc(7, GFP_KERNEL);
- if (!buf) {
+ buf_old = kzalloc(7, GFP_KERNEL);
+ if (!buf || buf_old) {
dev_err(&port->dev, "%s - out of memory.\n", __func__);
/* Report back no change occurred */
if (old_termios)
@@ -519,8 +512,8 @@ static void pl2303_set_termios(struct tty_struct *tty,
i = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
- 0, 0, buf, 7, 100);
- dev_dbg(&port->dev, "0xa1:0x21:0:0 %d - %7ph\n", i, buf);
+ 0, 0, buf_old, 7, 100);
+ dev_dbg(&port->dev, "0xa1:0x21:0:0 %d - %7ph\n", i, buf_old);
if (C_CSIZE(tty)) {
switch (C_CSIZE(tty)) {
@@ -591,6 +584,17 @@ static void pl2303_set_termios(struct tty_struct *tty,
dev_dbg(&port->dev, "parity = none\n");
}
+ /*
+ * Some PL2303 chips are reported to lose bytes if you change the
+ * serial settings even to the same values as before.
+ * At least HXD chips are affected, HX chips seem to be ok.
+ * Thus we actually need to filter in this specific case.
+ * NOTE: a tty_termios_hw_change() check isn't sufficient, because
+ * different baud rates can result in identic encoded values.
+ */
+ if (!memcmp(buf, buf_old, 7))
+ goto out;
+
i = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
0, 0, buf, 7, 100);
@@ -626,7 +630,9 @@ static void pl2303_set_termios(struct tty_struct *tty,
pl2303_vendor_write(0x0, 0x0, serial);
}
+out:
kfree(buf);
+ kfree(buf_old);
}
static void pl2303_dtr_rts(struct usb_serial_port *port, int on)
--
1.7.10.4
>From d303ff67ab1b817bf75b32eaa276369039ee4af2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Frank=20Sch=C3=A4fer?= <fschaefer.oss@xxxxxxxxxxxxxx>
Date: Fri, 1 Nov 2013 13:59:58 +0100
Subject: [PATCH] EXPERIMENTAL PATCH 2
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx>
---
drivers/usb/serial/pl2303.c | 29 ++++++++++++++++-------------
1 Datei geändert, 16 Zeilen hinzugefügt(+), 13 Zeilen entfernt(-)
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index bedf8e4..b0d3d66 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -155,6 +155,7 @@ struct pl2303_private {
spinlock_t lock;
u8 line_control;
u8 line_status;
+ u8 line_settings_enc[7]; /* baud rate, data bits, stop bits, parity */
};
static int pl2303_vendor_read(__u16 value, __u16 index,
@@ -500,14 +501,6 @@ static void pl2303_set_termios(struct tty_struct *tty,
int i;
u8 control;
- /*
- * 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;
-
buf = kzalloc(7, GFP_KERNEL);
if (!buf) {
dev_err(&port->dev, "%s - out of memory.\n", __func__);
@@ -517,11 +510,6 @@ static void pl2303_set_termios(struct tty_struct *tty,
return;
}
- i = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
- GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
- 0, 0, buf, 7, 100);
- dev_dbg(&port->dev, "0xa1:0x21:0:0 %d - %7ph\n", i, buf);
-
if (C_CSIZE(tty)) {
switch (C_CSIZE(tty)) {
case CS5:
@@ -591,10 +579,25 @@ static void pl2303_set_termios(struct tty_struct *tty,
dev_dbg(&port->dev, "parity = none\n");
}
+ /*
+ * Some PL2303 chips are reported to lose bytes if you change the
+ * serial settings even to the same values as before.
+ * At least HXD chips are affected, HX chips seem to be ok.
+ * Thus we actually need to filter in this specific case.
+ * NOTE: a tty_termios_hw_change() check isn't sufficient, because
+ * different baud rates can result in identic encoded values.
+ */
+ if (!memcmp(priv->line_settings_enc, buf, 7)) {
+ kfree(buf);
+ return;
+ }
+
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(buf, priv->line_settings_enc, 7);
/* change control lines if we are switching to or from B0 */
spin_lock_irqsave(&priv->lock, flags);
--
1.7.10.4
