This is a note to let you know that I've just added the patch titled
USB: serial: ch341: fix disabled rx timer on older devices
to the 5.19-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-disabled-rx-timer-on-older-devices.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 41ca302a697b64a3dab4676e01d0d11bb184737d Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Wed, 31 Aug 2022 10:15:25 +0200
Subject: USB: serial: ch341: fix disabled rx timer on older devices
From: Johan Hovold <johan@xxxxxxxxxx>
commit 41ca302a697b64a3dab4676e01d0d11bb184737d upstream.
At least one older CH341 appears to have the RX timer enable bit
inverted so that setting it disables the RX timer and prevents the FIFO
from emptying until it is full.
Only set the RX timer enable bit for devices with version newer than
0x27 (even though this probably affects all pre-0x30 devices).
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")
Cc: stable@xxxxxxxxxxxxxxx # 4.10
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/ch341.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -253,8 +253,12 @@ static int ch341_set_baudrate_lcr(struct
/*
* CH341A buffers data until a full endpoint-size packet (32 bytes)
* has been received unless bit 7 is set.
+ *
+ * At least one device with version 0x27 appears to have this bit
+ * inverted.
*/
- val |= BIT(7);
+ if (priv->version > 0x27)
+ val |= BIT(7);
r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER,
Patches currently in stable-queue which might be from johan@xxxxxxxxxx are
queue-5.19/usb-serial-option-add-support-for-oppo-r11-diag-port.patch
queue-5.19/usb-serial-ch341-fix-disabled-rx-timer-on-older-devices.patch
queue-5.19/usb-serial-ch341-fix-lost-character-on-lcr-updates.patch
queue-5.19/usb-serial-cp210x-add-decagon-uca-device-id.patch
queue-5.19/usb-serial-option-add-quectel-em060k-modem.patch
queue-5.19/usb-serial-option-add-support-for-cinterion-mv32-wa-wb-rmnet-mode.patch
queue-5.19/usb-serial-ftdi_sio-add-omron-cs1w-cif31-device-id.patch
