This is a note to let you know that I've just added the patch titled
USB: serial: pl2303: fix line-speed handling on newer chips
to the 5.11-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-pl2303-fix-line-speed-handling-on-newer-chips.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 979d9cbe75b922ab1695b8ad5576115774f72e62 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Mon, 11 Jan 2021 18:00:19 +0100
Subject: USB: serial: pl2303: fix line-speed handling on newer chips
From: Johan Hovold <johan@xxxxxxxxxx>
commit 979d9cbe75b922ab1695b8ad5576115774f72e62 upstream.
The latest chip family (HXN) apparently does not support setting the
line speed using divisors and instead needs to use the direct encoding
scheme for all rates.
This specifically enables 50, 110, 134, 200 bps and other rates not
supported by the original chip type.
Fixes: ebd09f1cd417 ("USB: serial: pl2303: add support for PL2303HXN")
Cc: stable@xxxxxxxxxxxxxxx # 5.5
Cc: Charles Yeh <charlesyeh522@xxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/pl2303.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -183,6 +183,7 @@ struct pl2303_type_data {
speed_t max_baud_rate;
unsigned long quirks;
unsigned int no_autoxonxoff:1;
+ unsigned int no_divisors:1;
};
struct pl2303_serial_private {
@@ -209,6 +210,7 @@ static const struct pl2303_type_data pl2
},
[TYPE_HXN] = {
.max_baud_rate = 12000000,
+ .no_divisors = true,
},
};
@@ -571,8 +573,12 @@ static void pl2303_encode_baud_rate(stru
baud = min_t(speed_t, baud, spriv->type->max_baud_rate);
/*
* Use direct method for supported baud rates, otherwise use divisors.
+ * Newer chip types do not support divisor encoding.
*/
- baud_sup = pl2303_get_supported_baud_rate(baud);
+ if (spriv->type->no_divisors)
+ baud_sup = baud;
+ else
+ baud_sup = pl2303_get_supported_baud_rate(baud);
if (baud == baud_sup)
baud = pl2303_encode_baud_rate_direct(buf, baud);
Patches currently in stable-queue which might be from johan@xxxxxxxxxx are
queue-5.11/usb-serial-pl2303-fix-line-speed-handling-on-newer-chips.patch
queue-5.11/usb-serial-mos7840-fix-error-code-in-mos7840_write.patch
queue-5.11/usb-serial-mos7720-fix-error-code-in-mos7720_write.patch
queue-5.11/usb-serial-ftdi_sio-fix-ftx-sub-integer-prescaler.patch
queue-5.11/usb-serial-option-update-interface-mapping-for-zte-p685m.patch
