From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Willy Tarreau <w@1wt.eu>,
Johan Hovold <johan@kernel.org>
Subject: [PATCH 4.4 11/25] USB: serial: ch341: fix character loss at high transfer rates
Date: Fri, 13 Aug 2021 17:06:35 +0200 [thread overview]
Message-ID: <20210813150521.087346803@linuxfoundation.org> (raw)
In-Reply-To: <20210813150520.718161915@linuxfoundation.org>
From: Willy Tarreau <w@1wt.eu>
commit 3c18e9baee0ef97510dcda78c82285f52626764b upstream.
The chip supports high transfer rates, but with the small default buffers
(64 bytes read), some entire blocks are regularly lost. This typically
happens at 1.5 Mbps (which is the default speed on Rockchip devices) when
used as a console to access U-Boot where the output of the "help" command
misses many lines and where "printenv" mangles the environment.
The FTDI driver doesn't suffer at all from this. One difference is that
it uses 512 bytes rx buffers and 256 bytes tx buffers. Adopting these
values completely resolved the issue, even the output of "dmesg" is
reliable. I preferred to leave the Tx value unchanged as it is not
involved in this issue, while a change could increase the risk of
triggering the same issue with other devices having too small buffers.
I verified that it backports well (and works) at least to 5.4. It's of
low importance enough to be dropped where it doesn't trivially apply
anymore.
Cc: stable@vger.kernel.org
Signed-off-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20210724152739.18726-1-w@1wt.eu
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/serial/ch341.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -585,6 +585,7 @@ 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,
next prev parent reply other threads:[~2021-08-13 15:09 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-13 15:06 [PATCH 4.4 00/25] 4.4.281-rc1 review Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 01/25] ALSA: seq: Fix racy deletion of subscriber Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 02/25] scsi: sr: Return correct event when media event code is 3 Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 03/25] media: videobuf2-core: dequeue if start_streaming fails Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 04/25] net: natsemi: Fix missing pci_disable_device() in probe and remove Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 05/25] mips: Fix non-POSIX regexp Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 06/25] bnx2x: fix an error code in bnx2x_nic_load() Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 07/25] net: pegasus: fix uninit-value in get_interrupt_interval Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 08/25] net: vxge: fix use-after-free in vxge_device_unregister Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 09/25] Bluetooth: defer cleanup of resources in hci_unregister_dev() Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 10/25] USB: serial: option: add Telit FD980 composition 0x1056 Greg Kroah-Hartman
2021-08-13 15:06 ` Greg Kroah-Hartman [this message]
2021-08-13 15:06 ` [PATCH 4.4 12/25] USB: serial: ftdi_sio: add device ID for Auto-M3 OP-COM v2 Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 13/25] scripts/tracing: fix the bug that cant parse raw_trace_func Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 14/25] media: rtl28xxu: fix zero-length control request Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 15/25] serial: 8250: Mask out floating 16/32-bit bus bits Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 16/25] MIPS: Malta: Do not byte-swap accesses to the CBUS UART Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 17/25] pcmcia: i82092: fix a null pointer dereference bug Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 18/25] reiserfs: add check for root_inode in reiserfs_fill_super Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 19/25] reiserfs: check directory items on read from disk Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 20/25] alpha: Send stop IPI to send to online CPUs Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 21/25] net/qla3xxx: fix schedule while atomic in ql_wait_for_drvr_lock and ql_adapter_reset Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 22/25] pipe: increase minimum default pipe size to 2 pages Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 23/25] USB:ehci:fix Kunpeng920 ehci hardware problem Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 24/25] net: xilinx_emaclite: Do not print real IOMEM pointer Greg Kroah-Hartman
2021-08-13 15:06 ` [PATCH 4.4 25/25] ovl: prevent private clone if bind mount is not allowed Greg Kroah-Hartman
2021-08-13 23:26 ` [PATCH 4.4 00/25] 4.4.281-rc1 review Shuah Khan
2021-08-14 14:20 ` Naresh Kamboju
2021-08-14 18:14 ` Guenter Roeck
2021-08-15 19:51 ` Pavel Machek
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