Revert "USB: serial: ch341: fix character loss at high transfer rates"

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
reads.

Reported-by: Paul Größel <pb.g@gmx.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=214131
Fixes: 3c18e9baee0e ("USB: serial: ch341: fix character loss at high transfer rates")
Cc: stable@vger.kernel.org
Cc: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20210824121926.19311-1-johan@kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index e6dce35ca1aa93c2bbb1033cdf54e0f79a1b7fbc..c87cb25e70ec5e45f4005a9314b0ce116d28f56d 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -625,7 +625,6 @@ static struct usb_serial_driver ch341_device = {
                .owner  = THIS_MODULE,
                .name   = "ch341-uart",
        },
-       .bulk_in_size      = 512,
        .id_table          = id_table,
        .num_ports         = 1,
        .open              = ch341_open,