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

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
>
>