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From:   Nix <nix@esperi.org.uk>
To:     Greg KH <greg@kroah.com>
Cc:     johan@kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: 4.20.7: pl2303 not working (post-4.19 regression) (limited info so far, not yet bisected)
References: <87o97bu2bt.fsf@esperi.org.uk> <20190216194758.GA10756@kroah.com>
Emacs:  a real time environment for simulating molasses-based life forms.
Date:   Sun, 17 Feb 2019 19:13:52 +0000
In-Reply-To: <20190216194758.GA10756@kroah.com> (Greg KH's message of "Sat, 16
        Feb 2019 20:47:58 +0100")
Message-ID: <877edytehb.fsf@esperi.org.uk>
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On 16 Feb 2019, Greg KH told this:

> On Sat, Feb 16, 2019 at 04:26:30PM +0000, Nix wrote:
>> So I just tried to connect up to my ancient Soekris firewall's serial
>> console to try to bisect a problem where it stopped booting in 4.20, and
>> found I couldn't.
>> 
>> minicom says:
>> 
>> minicom: cannot open /dev/ttyUSB0: Input/output error
>> 
>> and in the dmesg we see
>> 
>> [705576.028170] pl2303 ttyUSB0: failed to submit interrupt urb: -28
>>
>> Booting to 4.19, everything works fine. (A random GalliumOS Chromebook
[...]
>
> bisection would be great, thanks!

Rrrg. This is going to be harder than I thought. Rebooting, everything
works fine! So this is something that kicks in after something less than
eight days uptime, consistently on every box I own, but is fine on
reboot.

I'm still fairly sure this is a regression -- my machines are often up
for a lot longer than that and I've never seen this before I upgraded to
4.20.x -- but I don't think I'm going to identify it by mindless
bisection. I might have to actually *think* about it.