Weitao Wang 165cddba23 USB: Fix xhci event ring dequeue pointer ERDP update issue
[ Upstream commit e91ac20889d1a26d077cc511365cd7ff4346a6f3 ]

In some situations software handles TRB events slower than adding TRBs.
If the number of TRB events to be processed in a given interrupt is exactly
the same as the event ring size 256, then the local variable
"event_ring_deq" that holds the initial dequeue position is equal to
software_dequeue after handling all 256 interrupts.

It will cause driver to not update ERDP to hardware,

Software dequeue pointer is out of sync with ERDP on interrupt exit.
On the next interrupt, the event ring may full but driver will not
update ERDP as software_dequeue is equal to ERDP.

[  536.377115] xhci_hcd 0000:00:12.0: ERROR unknown event type 37
[  566.933173] sd 8:0:0:0: [sdb] tag#27 uas_eh_abort_handler 0 uas-tag 7 inflight: CMD OUT
[  566.933181] sd 8:0:0:0: [sdb] tag#27 CDB: Write(10) 2a 00 17 71 e6 78 00 00 08 00
[  572.041186] xhci_hcd On some situataions,the0000:00:12.0: xHCI host not responding to stop endpoint command.
[  572.057193] xhci_hcd 0000:00:12.0: Host halt failed, -110
[  572.057196] xhci_hcd 0000:00:12.0: xHCI host controller not responding, assume dead
[  572.057236] sd 8:0:0:0: [sdb] tag#26 uas_eh_abort_handler 0 uas-tag 6 inflight: CMD
[  572.057240] sd 8:0:0:0: [sdb] tag#26 CDB: Write(10) 2a 00 38 eb cc d8 00 00 08 00
[  572.057244] sd 8:0:0:0: [sdb] tag#25 uas_eh_abort_handler 0 uas-tag 5 inflight: CMD

Hardware ERDP is updated mid event handling if there are more than 128
events in an interrupt (half of ring size).
Fix this by updating the software local variable at the same time as
hardware ERDP.

[commit message rewording -Mathias]

Fixes: dc0ffbea5729 ("usb: host: xhci: update event ring dequeue pointer on purpose")
Reviewed-by: Peter Chen <peter.chen@kernel.org>
Signed-off-by: Weitao Wang <WeitaoWang-oc@zhaoxin.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220408134823.2527272-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-05-12 12:17:06 +02:00
..
2021-10-17 10:08:32 +02:00
2021-09-22 11:45:21 +02:00

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 ("hub_wq").

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.