From: Vladimir Stankovic <vladimir.stankovic@displaylink.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org, mausb-host-devel@displaylink.com
Subject: Re: [PATCH v5 5/8] usb: mausb_host: Introduce PAL processing
Date: Sun, 26 Apr 2020 14:32:51 +0200 [thread overview]
Message-ID: <48e45671-1f07-c994-8083-04199822c818@displaylink.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.2004252027360.13475-100000@netrider.rowland.org>
On 26.4.20. 02:32, Alan Stern wrote:
> On Sat, 25 Apr 2020 vladimir.stankovic@displaylink.com wrote:
>
>> Protocol adaptation layer (PAL) implementation has been added to
>> introduce MA-USB structures and logic.
>>
>> Signed-off-by: Vladimir Stankovic <vladimir.stankovic@displaylink.com>
>
> ...
>
>> + /*
>> + * Masking URB_SHORT_NOT_OK flag as SCSI driver is adding it where it
>> + * should not, so it is breaking the USB drive on the linux
>> + */
>> + urb->transfer_flags &= ~URB_SHORT_NOT_OK;
>
> Removing the SHORT_NOT_OK flag is _not_ a valid thing to do. It will
> cause drivers to malfunction.
>
> Can you please explain this comment?
>
> What SCSI driver?
>
> When is the flag being added?
>
> How does it break USB drives?
>
> Why haven't you already reported this problem to the
> appropriate maintainers?
>
> Alan Stern
>
Hi,
Issue that removal of SHORT_NOT_OK flag addressed is linked to particular
set of Kingston USB 3.0 flash drives (super speed) - other USB flash drives
haven't had this flag set. Without this "fix", those Kingston flash drives
are not being enumerated properly.
This particular line was added in the early stage of development, during
enumeration process implementation. The reason why it remained in the code
since is because we haven't noticed any side-effects, even with various
USB devices being attached to remote MA-USB device, including flash drives,
cameras, wireless mice, etc.
The problem has been reported, and is actively being investigated.
As soon as it gets addressed properly (w/o global negation of the flag),
a new patch will be pushed.
--
Regards,
Vladimir.
next prev parent reply other threads:[~2020-04-26 12:33 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-12 14:42 [PATCH v3 0/8] Add MA USB Host driver Vladimir Stankovic
2020-03-27 15:26 ` [PATCH v4 " vladimir.stankovic
2020-03-27 15:26 ` [PATCH v4 1/8] usb: Add MA-USB Host kernel module vladimir.stankovic
2020-03-27 16:25 ` Alan Stern
2020-03-27 15:26 ` [PATCH v4 2/8] usb: mausb_host: Add link layer implementation vladimir.stankovic
2020-03-27 15:26 ` [PATCH v4 3/8] usb: mausb_host: HCD initialization vladimir.stankovic
2020-03-27 15:26 ` [PATCH v4 4/8] usb: mausb_host: Implement initial hub handlers vladimir.stankovic
2020-03-27 16:37 ` Alan Stern
2020-04-13 15:16 ` Vladimir Stankovic
2020-03-27 15:26 ` [PATCH v4 5/8] usb: mausb_host: Introduce PAL processing vladimir.stankovic
2020-03-27 16:35 ` Alan Stern
2020-03-28 3:56 ` kbuild test robot
2020-03-27 15:26 ` [PATCH v4 6/8] usb: mausb_host: Add logic for PAL-to-PAL communication vladimir.stankovic
2020-03-27 15:26 ` [PATCH v4 7/8] usb: mausb_host: MA-USB PAL events processing vladimir.stankovic
2020-03-28 10:35 ` kbuild test robot
2020-04-04 16:07 ` kbuild test robot
2020-03-27 15:26 ` [PATCH v4 8/8] usb: mausb_host: Process MA-USB data packets vladimir.stankovic
2020-04-25 9:19 ` [PATCH v5 0/8] Add MA USB Host driver vladimir.stankovic
2020-04-25 9:19 ` [PATCH v5 1/8] usb: Add MA-USB Host kernel module vladimir.stankovic
2020-04-28 11:03 ` Greg KH
2020-04-25 9:19 ` [PATCH v5 2/8] usb: mausb_host: Add link layer implementation vladimir.stankovic
2020-04-25 9:19 ` [PATCH v5 3/8] usb: mausb_host: HCD initialization vladimir.stankovic
2020-04-28 11:07 ` Greg KH
2020-04-25 9:19 ` [PATCH v5 4/8] usb: mausb_host: Implement initial hub handlers vladimir.stankovic
2020-04-25 9:19 ` [PATCH v5 5/8] usb: mausb_host: Introduce PAL processing vladimir.stankovic
2020-04-26 0:32 ` Alan Stern
2020-04-26 12:32 ` Vladimir Stankovic [this message]
2020-04-26 14:31 ` Alan Stern
2020-04-26 14:45 ` [External] " Vladimir Stankovic
2020-04-26 20:56 ` Alan Stern
2020-04-30 14:37 ` Vladimir Stankovic
2020-04-30 15:18 ` Alan Stern
2020-04-30 15:34 ` Vladimir Stankovic
2020-04-30 15:41 ` Alan Stern
2020-04-25 9:19 ` [PATCH v5 6/8] usb: mausb_host: Add logic for PAL-to-PAL communication vladimir.stankovic
2020-04-25 9:19 ` [PATCH v5 7/8] usb: mausb_host: MA-USB PAL events processing vladimir.stankovic
2020-04-28 11:08 ` Greg KH
2020-04-25 9:19 ` [PATCH v5 8/8] usb: mausb_host: Process MA-USB data packets vladimir.stankovic
2020-04-28 11:04 ` [PATCH v5 0/8] Add MA USB Host driver Greg KH
2020-04-30 16:51 ` [External] " Vladimir Stankovic
2020-04-30 20:02 ` Greg KH
2020-05-15 13:04 ` Vladimir Stankovic
2020-05-29 12:48 ` Pavel Machek
2020-05-15 12:34 ` [PATCH v6 " Vladimir Stankovic
2020-05-15 12:34 ` [PATCH v6 1/8] usb: Add MA-USB Host kernel module Vladimir Stankovic
2020-05-15 13:01 ` Greg KH
2020-06-11 18:20 ` Vladimir Stankovic
2020-05-15 13:02 ` Greg KH
2020-06-11 18:19 ` [External] " Vladimir Stankovic
2020-05-15 12:34 ` [PATCH v6 2/8] usb: mausb_host: Add link layer implementation Vladimir Stankovic
2020-05-15 12:34 ` [PATCH v6 3/8] usb: mausb_host: HCD initialization Vladimir Stankovic
2020-05-15 13:03 ` Greg KH
2020-06-11 18:19 ` Vladimir Stankovic
2020-05-15 13:07 ` Greg KH
2020-06-11 18:18 ` [External] " Vladimir Stankovic
2020-06-18 8:18 ` Greg KH
2020-05-15 12:34 ` [PATCH v6 4/8] usb: mausb_host: Implement initial hub handlers Vladimir Stankovic
2020-05-15 12:34 ` [PATCH v6 5/8] usb: mausb_host: Introduce PAL processing Vladimir Stankovic
2020-05-15 12:35 ` [PATCH v6 6/8] usb: mausb_host: Add logic for PAL-to-PAL communication Vladimir Stankovic
2020-05-15 12:35 ` [PATCH v6 7/8] usb: mausb_host: MA-USB PAL events processing Vladimir Stankovic
2020-05-15 12:35 ` [PATCH v6 8/8] usb: mausb_host: Process MA-USB data packets Vladimir Stankovic
2020-05-15 13:08 ` [PATCH v6 0/8] Add MA USB Host driver Greg KH
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