This is a note to let you know that I've just added the patch titled
USB: serial: ch341: fix lost character on LCR updates
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-serial-ch341-fix-lost-character-on-lcr-updates.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Sep 6 03:17:57 PM CEST 2022
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Tue, 6 Sep 2022 14:21:26 +0200
Subject: USB: serial: ch341: fix lost character on LCR updates
To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, Johan Hovold <johan@xxxxxxxxxx>, Jonathan Woithe <jwoithe@xxxxxxxxxx>
Message-ID: <20220906122127.31321-2-johan@xxxxxxxxxx>
From: Johan Hovold <johan@xxxxxxxxxx>
commit 8e83622ae7ca481c76c8fd9579877f6abae64ca2 upstream.
Disable LCR updates for pre-0x30 devices which use a different (unknown)
protocol for line control and where the current register write causes
the next received character to be lost.
Note that updating LCR using the INIT command has no effect on these
devices either.
Reported-by: Jonathan Woithe <jwoithe@xxxxxxxxxx>
Tested-by: Jonathan Woithe <jwoithe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/Ys1iPTfiZRWj2gXs@xxxxxxxxxxxxxxxxxxx
Fixes: 4e46c410e050 ("USB: serial: ch341: reinitialize chip on reconfiguration")
Fixes: 55fa15b5987d ("USB: serial: ch341: fix baud rate and line-control handling")
Cc: stable@xxxxxxxxxxxxxxx # 4.10
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
[ johan: adjust context to 5.15 ]
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/ch341.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -97,7 +97,10 @@ struct ch341_private {
u8 mcr;
u8 msr;
u8 lcr;
+
unsigned long quirks;
+ u8 version;
+
unsigned long break_end;
};
@@ -271,6 +274,9 @@ static int ch341_set_baudrate_lcr(struct
* (stop bits, parity and word length). Version 0x30 and above use
* CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero.
*/
+ if (priv->version < 0x30)
+ return 0;
+
r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr);
if (r)
@@ -323,7 +329,9 @@ static int ch341_configure(struct usb_de
r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
if (r < 0)
goto out;
- dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
+
+ priv->version = buffer[0];
+ dev_dbg(&dev->dev, "Chip version: 0x%02x\n", priv->version);
r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
if (r < 0)
Patches currently in stable-queue which might be from johan@xxxxxxxxxx are
queue-5.15/usb-serial-option-add-support-for-oppo-r11-diag-port.patch
queue-5.15/usb-serial-ch341-fix-disabled-rx-timer-on-older-devices.patch
queue-5.15/usb-dwc3-disable-usb-core-phy-management.patch
queue-5.15/usb-dwc3-qcom-fix-use-after-free-on-runtime-pm-wakeup.patch
queue-5.15/usb-dwc3-fix-phy-disable-sequence.patch
queue-5.15/usb-serial-ch341-fix-lost-character-on-lcr-updates.patch
queue-5.15/usb-serial-cp210x-add-decagon-uca-device-id.patch
queue-5.15/usb-serial-option-add-quectel-em060k-modem.patch
queue-5.15/usb-serial-option-add-support-for-cinterion-mv32-wa-wb-rmnet-mode.patch
queue-5.15/usb-serial-ftdi_sio-add-omron-cs1w-cif31-device-id.patch
