From: Steve Markgraf <steve@steve-m.de>
To: Johan Hovold <johan@kernel.org>
Cc: linux-usb@vger.kernel.org
Subject: Re: Regression in 5.5.0-rc6 for FL2000 USB 3.0 to VGA adapter
Date: Sun, 19 Jan 2020 15:48:32 +0100 [thread overview]
Message-ID: <734d9503-29ef-2fa0-5df8-6ef5701d3d61@steve-m.de> (raw)
In-Reply-To: <20200119135811.GY2301@localhost>
Hi Johan,
On 19.01.20 14:58, Johan Hovold wrote:
> I just took a quick look at the libosmo-fl2k code and it appears that
> you claim both interfaces but never set alternate setting 1 for
> interface 0, which would enable those endpoints.
>
> Could you see if that's all that's needed to get your application
> working again?
Yes, you are right, I had another look at it today and tried exactly
that, and it's working now with altsetting 1 of interface 0.
I will push a change to osmo-fl2k shortly.
There is also an out-of-tree kernel driver that makes use of this
device, and might even need interface 1, but I haven't verified this so
far:
https://github.com/FrescoLogic/FL2000
The question is if there are other devices out there where there are
duplicate endpoints on different interfaces. The spec clearly states
that this is forbidden, but the USBx0CV Chapter 9 tests do not test for
this and pass just fine, so I assume the FL2000 will not be the only
device in the market where this mistake has been made.
Regards,
Steve
next prev parent reply other threads:[~2020-01-19 14:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-18 23:52 Regression in 5.5.0-rc6 for FL2000 USB 3.0 to VGA adapter Steve Markgraf
2020-01-19 12:58 ` Greg KH
2020-01-19 12:59 ` Greg KH
2020-01-19 13:58 ` Johan Hovold
2020-01-19 14:48 ` Steve Markgraf [this message]
2020-01-19 15:15 ` Johan Hovold
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