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Streams on the EJ168 do not work as they should. I've spend 2 days trying to get them to work, but without success. The first problem is that when ever you ring the stream-ring doorbell, the controller starts executing trbs at the beginning of the first ring segment, event if it ended somewhere else previously. This can be worked around by allowing enqueing only one td (not a problem with how streams are typically used) and then resetting our copies of the enqueueing en dequeueing pointers on a td completion to match what the controller seems to be doing. This way things seem to start working with uas and instead of being able to complete only the very first scsi command, the scsi core can probe the disk. But then things break later on when td-s get enqueued with more then one trb. The controller does seem to increase its dequeue pointer while executing a stream-ring (data transfer events I inserted for debugging do trigger). However execution seems to stop at the final normal trb of a multi trb td, even if there is a data transfer event inserted after the final trb. The first problem alone is a serious deviation from the spec, and esp. dealing with cancellation would have been very tricky if not outright impossible, but the second problem simply is a deal breaker altogether, so this patch simply disables streams. Note this will cause the usb-storage + uas driver pair to automatically switch to using usb-storage instead of uas on these devices, essentially reverting to the 3.14 and earlier behavior when uas was marked CONFIG_BROKEN. https://bugzilla.redhat.com/show_bug.cgi?id=1121288 https://bugzilla.kernel.org/show_bug.cgi?id=80101 Cc: stable@vger.kernel.org # 3.15 Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| core | ||
| dwc2 | ||
| dwc3 | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| phy | ||
| renesas_usbhs | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| usb-skeleton.c | ||
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.