Date: Tue, 12 Apr 2022 16:04:20 -0700 From: Bakul Shah <bakul@iitbombay.org> To: mahesh mv <maheshm_v@yahoo.com> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: xhci USB transaction error and subsequent recovery mechanism on Freebsd stable/12 Message-ID: <1EA26D91-EBA0-4043-BC29-06B7578AAE05@iitbombay.org> In-Reply-To: <1524993805.98701.1649776236883@mail.yahoo.com> References: <1524993805.98701.1649776236883.ref@mail.yahoo.com> <1524993805.98701.1649776236883@mail.yahoo.com>
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On Apr 12, 2022, at 8:10 AM, mahesh mv <maheshm_v@yahoo.com> wrote:
>
> This issue was never observed with Linux kernel 5.4.2 on the same HW.
On an external SSD I have, Linux was using UAS (USB
Attached SCSI), while FreeBSD used the older BOT (Bulk
Only Transport) protocol. See if your disk supports both.
You can try
usbconfig -d genN.M dump_all_desc # N = unit, M=device index
to dump all the descriptors and see what all it supports.
You should see something like this:
# !! | grep Protocol
bDeviceProtocol = 0x0000
bInterfaceProtocol = 0x0050 -- BOT
bInterfaceProtocol = 0x0062 -- UAS
Likely a remote possibility but could it be that it has a
bug in the disk's BOT implementation? At any rate you can
check if anyone else with the exact disk model has similar
issues. Alternately, see if the problem disappears with a
different disk. Another thing to check is whether the disk
has any updated firmware.
Note: I am not a USB expert so apologies in advance if this
leads you astray! My main point being that the issue may not
necessarily be a FreeBSD bug.
Do share the USB traces.
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