[PATCH 4.14 03/23] Revert "USB: serial: ch341: fix character loss at high transfer rates"

From: Greg Kroah-Hartman
Date: Wed Sep 01 2021 - 08:29:44 EST

From: Johan Hovold <johan@xxxxxxxxxx>

commit df7b16d1c00ecb3da3a30c999cdb39f273c99a2f upstream.

This reverts commit 3c18e9baee0ef97510dcda78c82285f52626764b.

These devices do not appear to send a zero-length packet when the
transfer size is a multiple of the bulk-endpoint max-packet size. This
means that incoming data may not be processed by the driver until a
short packet is received or the receive buffer is full.

Revert back to using endpoint-sized receive buffers to avoid stalled

Reported-by: Paul Größel <pb.g@xxxxxx>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=214131
Fixes: 3c18e9baee0e ("USB: serial: ch341: fix character loss at high transfer rates")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Willy Tarreau <w@xxxxxx>
Link: https://lore.kernel.org/r/20210824121926.19311-1-johan@xxxxxxxxxx
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/usb/serial/ch341.c | 1 -
1 file changed, 1 deletion(-)

--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -628,7 +628,6 @@ static struct usb_serial_driver ch341_de
.owner = THIS_MODULE,
.name = "ch341-uart",
- .bulk_in_size = 512,
.id_table = id_table,
.num_ports = 1,
.open = ch341_open,