From: Johan Hovold <johan@kernel.org>
To: David Frey <dpfrey@gmail.com>
Cc: "Alex Villacís Lasso" <a_villacis@palosanto.com>,
linux-usb@vger.kernel.org, "Pho Tran" <pho.tran@silabs.com>,
"Tung Pham" <tung.pham@silabs.com>,
Hung.Nguyen@silabs.com
Subject: Re: cp210x module broken in 5.12.5 and 5.12.6, works in 5.11.21 (with bisection)
Date: Sat, 5 Jun 2021 12:13:03 +0200 [thread overview]
Message-ID: <YLtOL5aZUnntfqWB@hovoldconsulting.com> (raw)
In-Reply-To: <CAAvkfd-vmi_VJrCQg-ktF+sZZUfb5J+DJfjHv=TdVafyj1m1Ew@mail.gmail.com>
On Fri, Jun 04, 2021 at 04:16:26PM -0700, David Frey wrote:
> I'm not sure if this matters, but I have been told that the failing
> boards have CP2102N chips with"A01" firmware. I tried to install
> SIlicon Labs Simplicity Studio on Windows because I read that it would
> be able to identify the firmware version of the device, but I couldn't
> actually figure out how to find the information. If someone can tell
> me a way to get the firmware version, I can check to see if it's
> different between the device that does exhibit this failure and the
> one that doesn't.
That is definitely worth pursuing. The A01 is apparently EOLed and
there's a later A02 and possibly even A03:
https://www.silabs.com/community/interface/knowledge-base.entry.html/2020/03/31/how_to_determinecp2102nrevisiona01vsa02-DCJI
That page refers to that vendor tool "Simplicity Studio" as well as a
Windows library described by
https://www.silabs.com/documents/public/application-notes/AN978-cp210x-usb-to-uart-api-specification.pdf
that can be used to read out the firmware version on CP2102N and CP2108
(three bytes). We just need to figure out which vendor request the
library (and tool) uses and we could key off of this in the driver if
this turns out to be related to the firmware revision.
If anyone's got a Windows installation it may be possible to dump the
USB traffic using Wireshark to determine the request. Unless Silabs can
chime in here of course.
I found an errata for A01 on here, but no mention if this particular
bug:
https://www.silabs.com/documents/public/pcns/190315471-CP2102N-Product-Revision-with-Datasheet-and-Errata-Update.pdf
> On Fri, Jun 4, 2021 at 8:42 AM Johan Hovold <johan@kernel.org> wrote:
> > This all matches the CP2102N I've got here and which can set RTS just
> > fine also with the IXOFF limits set (unlike your device).
> >
> > Unless there's some other configuration setting causing it would seem
> > your device firmware is just buggy (and bcdDevice was not updated when
> > it was fixed, which seems unlikely).
Johan
next prev parent reply other threads:[~2021-06-05 10:13 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 17:38 cp210x module broken in 5.12.5 and 5.12.6, works in 5.11.21 (with bisection) Alex Villacís Lasso
2021-06-01 7:50 ` Johan Hovold
2021-06-01 14:51 ` Alex Villacís Lasso
2021-06-01 15:40 ` Johan Hovold
2021-06-01 17:18 ` Alex Villacís Lasso
2021-06-02 14:50 ` Johan Hovold
2021-06-02 15:54 ` Alex Villacís Lasso
2021-06-04 15:42 ` Johan Hovold
2021-06-04 18:25 ` Alex Villacís Lasso
2021-06-05 10:24 ` Johan Hovold
2021-06-05 10:54 ` Johan Hovold
2021-06-04 23:16 ` David Frey
2021-06-05 10:13 ` Johan Hovold [this message]
2021-06-07 15:16 ` Alex Villacís Lasso
2021-06-07 16:45 ` Johan Hovold
2021-06-07 16:44 ` David Frey
2021-06-07 16:52 ` Johan Hovold
2021-06-07 18:02 ` David Frey
2021-06-07 20:44 ` David Frey
2021-06-07 23:50 ` Alex Villacís Lasso
2021-06-08 9:10 ` Tung Pham
2021-06-08 9:52 ` Johan Hovold
2021-06-08 9:41 ` Johan Hovold
2021-06-09 16:15 ` [PATCH] USB: serial: cp210x: fix CP2102N-A01 modem control Johan Hovold
2021-06-09 17:00 ` Alex Villacís Lasso
2021-06-10 7:23 ` Johan Hovold
2021-06-10 14:55 ` Alex Villacís Lasso
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