From: Alan Stern <stern@rowland.harvard.edu>
To: Vladimir Stankovic <vladimir.stankovic@displaylink.com>
Cc: gregkh@linuxfoundation.org, <linux-kernel@vger.kernel.org>,
<linux-usb@vger.kernel.org>, <mausb-host-devel@displaylink.com>
Subject: Re: [External] Re: [PATCH v5 5/8] usb: mausb_host: Introduce PAL processing
Date: Thu, 30 Apr 2020 11:41:57 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.2004301139560.3855-100000@netrider.rowland.org> (raw)
In-Reply-To: <32cc80c0-c2ff-440c-7505-e848aba782d8@displaylink.com>
On Thu, 30 Apr 2020, Vladimir Stankovic wrote:
> On 30.4.20. 17:18, Alan Stern wrote:
> > On Thu, 30 Apr 2020, Vladimir Stankovic wrote:
> >
> >> On 26.4.20. 22:56, Alan Stern wrote:
> >>> On Sun, 26 Apr 2020, Vladimir Stankovic wrote:
> >>>
> >>>> On 26.4.20. 16:31, Alan Stern wrote:
> >>>>> On Sun, 26 Apr 2020, Vladimir Stankovic wrote:
> >>>>>
> >>>>>> 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;
> >
> > ...
> > Also, what makes you think the driver is setting the SHORT_NOT_OK flag
> > at the wrong time? In fact, how can there be a wrong time?
> > SHORT_NOT_OK is a valid flag to use with any control or bulk URB.
> >
> > Alan Stern
> >
> The comment is clearly wrong - as mentioned earlier, this fix was added in early
> development phase and I guess that implementer was not clear on how the particular
> flag was added. Investigation is ongoing around proper fix for this.
>
> Anyhow, it is a usb-storage driver related to this - here is usb-related log snippet:
>
> usb 3-1.1.2: new high-speed USB device number 5 using mausb_host_hcd_dev
> usb 3-1.1.2: New USB device found, idVendor=0951, idProduct=1666
> usb 3-1.1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
> usb 3-1.1.2: Product: DataTraveler 3.0
> usb 3-1.1.2: Manufacturer: Kingston
> usb 3-1.1.2: SerialNumber: 0C9D9210E304E311095E087A
> usb-storage 3-1.1.2:1.0: USB Mass Storage device detected
> scsi host3: usb-storage 3-1.1.2:1.0
> scsi 3:0:0:0: Direct-Access Kingston DataTraveler 3.0 PMAP PQ: 0 ANSI: 6
> Attached scsi generic sg2 type 0
> [sdb] 30277632 512-byte logical blocks: (15.5 GB/14.4 GiB)
>
> As can be seen, USB flash attached to remote device is properly enumerated via
> MA USB. Without the fix, usb driver is not able to read USB descriptors, ending
> up in USB storage not being accessible.
That's strange, considering that the SHORT_NOT_OK flag doesn't get set
when the system is reading the device's USB descriptors.
Alan Stern
next prev parent reply other threads:[~2020-04-30 15:42 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
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 [this message]
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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