USB: Fix xhci event ring dequeue pointer ERDP update issue
authorWeitao Wang <WeitaoWang-oc@zhaoxin.com>
Fri, 8 Apr 2022 13:48:21 +0000 (16:48 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 9 May 2022 07:05:00 +0000 (09:05 +0200)
commit23b0711fcd3ccc8c23a8848e6b387aae9f4af8c4
tree158b4df6d051e6f57c6a84235e42859436055a21
parent712302aed104fb037a3e28874679935f79587df7
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>
drivers/usb/host/xhci-ring.c