Re: removing certain umass (cd/dvd?) devices appears to lock up the USB bus on 14.2/14.3 (at least)

On Tue, Aug 12, 2025, 10:33 PM David Cross <david@crossfamilyweb.com> wrote:

> I am upgrading one of my machines to 15.0 now; though the last 2 times I
> tried to repro on 14.3 it failed (after I had posted the initial example of
> a failure on 14.3).  I will be trying a few more times on 14.3 with
> different configs, this machine should be on 15.0 by tomorrow AM.)
>

That will tell us if this is a usb stack bug (if it doesn't work) or
something we have a patch for :)... I'm hoping for the latter.

Warner

> On 8/12/25 16:12, Warner Losh wrote:
>
> Hey David,
>
> Did you get a chance to try the USB sticks with -current yet?
>
> Warner
>
> On Thu, Aug 7, 2025 at 12:54 PM Warner Losh <imp@bsdimp.com> wrote:
>
>> Maybe you could try 15.0. I've done a lot to fix these things in 15.0.
>> If it still happens there, we'll talk about changes. I've not MFC'd
>> the changes I've made since they are kinda extensive. On the other
>> hand, there's been a lot of reports of 'works better for me' with only
>> one regression. On the other hand, it's not entirely clear this is in
>> the class of problems I solved.
>>
>> Sadly, I suspect that we'll need to have hardware in the right hands
>> to solve this completely, especially since the reproduction appears to
>> be hit or miss. Is this a pure DVD drive? Is it portable or desktop?
>> If it's the one I found on ebay (https://www.ebay.com/itm/396752411077
>> though there's others), looks in budget for me to obtain to help if
>> there's a reliable recipe to reproduce and it's not the "fault" of
>> your host USB chipset.
>>
>> Warner
>>
>> On Thu, Aug 7, 2025 at 12:43 PM David Cross <david@crossfamilyweb.com>
>> wrote:
>> >
>> > I have a USB DVD drive that when I unplug (even when empty and
>> > unmounted) appears to stop the entire USB stack on 14.2/14.3. There are
>> > no errors (that I can see) in the dmesg, it *appears* to detach, but
>> > then no other USB events happen.
>> >
>> >
>> > I originally thought it was just the port that it was attached to, but
>> > in recent experimentation I attached it to a USB hub, then detached it
>> > from the hub, and even other ports on the host stopped responding.
>> > Currently connected devices appear to continue to work, but if removed
>> > nothing will reattach to those ports.
>> >
>> >
>> > This has now happened across a couple of different machines with this
>> > device, so I don't think it is host specific behavior
>> >
>> >
>> > When trying to run 'usbconfig -v - l' to get some kind of diagnostics it
>> > just hangs; C-t yields the following:
>> >
>> >
>> >  > load: 0.12  cmd: usbconfig 52496 [USB config SX lock] 3.12r 0.00u
>> > 0.00s 0% 2280k
>> >
>> >
>> > Of course in the interests of a fresh reproduction for this email, it
>> > just worked; I am continuing to attempt to reproduce. Suggestions of
>> > things I should try when I am successful to diagnose the issue so we can
>> > fix it?
>> >
>> > The relevant USB attach messages are:
>> >
>> > ugen1.10: <Hitachi-LG Data Storage Inc Portable Super Multi Drive> at
>> usbus1
>> > umass0 on uhub4
>> > umass0: <Hitachi-LG Data Storage Inc Portable Super Multi Drive, class
>> > 0/0, rev 2.00/0.00, addr 14> on usbus1
>> > umass0:  8070i (ATAPI) over Bulk-Only; quirks = 0x0000
>> > umass0:1:0: Attached to scbus1
>> > cd0 at umass-sim0 bus 0 scbus1 target 0 lun 0
>> > cd0: <HL-DT-ST DVDRAM SP80NB80 RC00> Removable CD-ROM SCSI device
>> > cd0: 40.000MB/s transfers
>> > cd0: 0MB (1 0 byte sectors)
>> > cd0: quirks=0x10<10_BYTE_ONLY>
>> >
>> > Detach messages are:
>> >
>> > ugen1.10: <Hitachi-LG Data Storage Inc Portable Super Multi Drive> at
>> > usbus1 (disconnected)
>> > umass0: at uhub4, port 2, addr 14 (disconnected)
>> > cd0 at umass-sim0 bus 0 scbus1 target 0 lun 0
>> > cd0: <HL-DT-ST DVDRAM SP80NB80 RC00>  detached
>> > (cd0:umass-sim0:0:0:0): Periph destroyed
>> > umass0: detached
>> >
>> >
>>
>