NetBSD Problem Report #53913

From www@NetBSD.org  Sun Jan 27 09:40:19 2019
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Message-Id: <20190127094018.397227A1F0@mollari.NetBSD.org>
Date: Sun, 27 Jan 2019 09:40:18 +0000 (UTC)
From: vezhlys@gmail.com
Reply-To: vezhlys@gmail.com
To: gnats-bugs@NetBSD.org
Subject: 4World USB to Serial adapter fails on connection
X-Send-Pr-Version: www-1.0

>Number:         53913
>Category:       kern
>Synopsis:       4World USB to Serial adapter fails on connection
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jan 27 09:45:00 +0000 2019
>Closed-Date:    Sat Feb 02 21:44:44 +0000 2019
>Last-Modified:  Sat Feb 02 21:44:44 +0000 2019
>Originator:     Andrius V
>Release:        8.99.30
>Organization:
>Environment:
NetBSD vertexpc 8.99.30 NetBSD 8.99.30 (GENERIC) #0: Tue Jan 15 14:23:56 UTC 2019  mkrepro@mkrepro.NetBSD.org:/usr/src/sys/arch/i386/compile/GENERIC i386
>Description:
I've recently bought 4World USB to Serial adapter which is based on WinChipHead CH341/340 chip.

from dmesg:
uchcom0: QinHeng Electronics (0x1a86) USB2.0-Ser! (0x7523), rev 1.10/2.54, addr 3
ucom0 at uchcom0
uchcom0: WARNING: power management not supported

Unfortunately, when I am trying to use with minicom (or any alternative app), I am receiving this error message:
uchcom0: cannot reset: STALLED

I investigated it minimally and it returns error on the second call in reset_chip method:
err = read_reg(sc, UCHCOM_REG_BPS_PRE, &pre, UCHCOM_REG_BPS_DIV, &div);

So, I checked OpenBSD driver and it seams they simplified reset code with some hardcoded values. I actually tried it and OpenBSD code works for me (with default configuration at least). minicom successfully started, communication between PCs was successful too. OpenBSD commit can be seen here https://github.com/openbsd/src/commit/5165e579a145cd62a9fbbbd8c33e30b50d88b5d1#diff-e15f5490917f699be5d06d933f46a0b2. 

However, I am not sure if it's desirable solution for NetBSD since I saw some recent development on the driver (issue is the same before or after those changes).
>How-To-Repeat:
Connect the cable to USB, try to start minicom with /dev/ttyU0 device. Check dmesg messages.
>Fix:
Workaround copied from OpenBSD:

Index: sys/dev/usb/uchcom.c
==================================================================
--- sys/dev/usb/uchcom.c
+++ sys/dev/usb/uchcom.c
@@ -116,10 +116,17 @@
 #define UCHCOM_INTR_LEAST	4

 #define UCHCOMIBUFSIZE 256
 #define UCHCOMOBUFSIZE 256

+/*
+ * XXX - these magic numbers come from Linux (drivers/usb/serial/ch341.c).
+ * The manufacturer was unresponsive when asked for documentation.
+ */
+#define UCHCOM_RESET_VALUE	0x501F	/* line mode? */
+#define UCHCOM_RESET_INDEX	0xD90A	/* baud rate? */
+
 struct uchcom_softc
 {
 	device_t		sc_dev;
 	struct usbd_device *	sc_udev;
 	device_t		sc_subdev;
@@ -761,31 +768,12 @@

 static int
 reset_chip(struct uchcom_softc *sc)
 {
 	usbd_status err;
-	uint8_t lcr, lcr2, pre, div;
-	uint16_t val=0, idx=0;
-
-	err = read_reg(sc, UCHCOM_REG_LCR, &lcr, UCHCOM_REG_LCR2, &lcr2);
-	if (err)
-		goto failed;
-
-	err = read_reg(sc, UCHCOM_REG_BPS_PRE, &pre, UCHCOM_REG_BPS_DIV, &div);
-	if (err)
-		goto failed;
-
-	val |= (uint16_t)lcr << 8;
-	val |= 0x9c;	/* magic from vendor Linux and Android drivers */
-	idx |= pre & 0x07;
-	idx |= (uint16_t)div << 8;
-	idx |= UCHCOM_BPS_PRE_IMM;
-
-	DPRINTF(("%s: reset v=0x%04X, i=0x%04X\n",
-		 device_xname(sc->sc_dev), val, idx));
-
-	err = generic_control_out(sc, UCHCOM_REQ_RESET, val, idx);
+	
+	err = generic_control_out(sc, UCHCOM_REQ_RESET, UCHCOM_RESET_VALUE, UCHCOM_RESET_INDEX);
 	if (err)
 		goto failed;

 	return 0;

>Release-Note:

>Audit-Trail:
From: "Jonathan A. Kollasch" <jakllsch@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/53913 CVS commit: src/sys/dev/usb
Date: Thu, 31 Jan 2019 18:21:21 +0000

 Module Name:	src
 Committed By:	jakllsch
 Date:		Thu Jan 31 18:21:21 UTC 2019

 Modified Files:
 	src/sys/dev/usb: uchcom.c

 Log Message:
 Reset the hardware like other drivers do for better compatibility with
 more chip firmware versions.

 From (and should fix) PR kern/53913.


 To generate a diff of this commit:
 cvs rdiff -u -r1.27 -r1.28 src/sys/dev/usb/uchcom.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

From: Andrius V <vezhlys@gmail.com>
To: gnats-bugs@netbsd.org, jakllsch@netbsd.org
Cc: kern-bug-people@netbsd.org, gnats-admin@netbsd.org, netbsd-bugs@netbsd.org
Subject: Re: PR/53913 CVS commit: src/sys/dev/usb
Date: Sat, 2 Feb 2019 23:01:43 +0200

 Thank you for the commit. For me it definitely fixes the issue since
 commit is more or less the same to my manually applied changes
 described in bug report. Tested with up to date current code to be
 sure.

 On Thu, Jan 31, 2019 at 8:25 PM Jonathan A. Kollasch
 <jakllsch@netbsd.org> wrote:
 >
 > The following reply was made to PR kern/53913; it has been noted by GNATS.
 >
 > From: "Jonathan A. Kollasch" <jakllsch@netbsd.org>
 > To: gnats-bugs@gnats.NetBSD.org
 > Cc:
 > Subject: PR/53913 CVS commit: src/sys/dev/usb
 > Date: Thu, 31 Jan 2019 18:21:21 +0000
 >
 >  Module Name:   src
 >  Committed By:  jakllsch
 >  Date:          Thu Jan 31 18:21:21 UTC 2019
 >
 >  Modified Files:
 >         src/sys/dev/usb: uchcom.c
 >
 >  Log Message:
 >  Reset the hardware like other drivers do for better compatibility with
 >  more chip firmware versions.
 >
 >  From (and should fix) PR kern/53913.
 >
 >
 >  To generate a diff of this commit:
 >  cvs rdiff -u -r1.27 -r1.28 src/sys/dev/usb/uchcom.c
 >
 >  Please note that diffs are not public domain; they are subject to the
 >  copyright notices on the relevant files.
 >

State-Changed-From-To: open->closed
State-Changed-By: dholland@NetBSD.org
State-Changed-When: Sat, 02 Feb 2019 21:44:44 +0000
State-Changed-Why:
confirmed fixed, thanks.


>Unformatted:

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