APPLIED[artful]: [SRU Zesty][PATCH 1/1] usb: xhci: Issue stop EP command only when the EP state is running

Seth Forshee seth.forshee at
Wed Aug 23 12:22:10 UTC 2017

On Wed, Aug 16, 2017 at 02:03:06PM +0200, Alberto Milone wrote:
> From: Shyam Sundar S K <Shyam-sundar.S-k at>
> on AMD platforms with SNPS 3.1 USB controller if stop endpoint command is
> issued the controller does not respond, when the EP is not in running
> state. HW completes the command execution and reports
> "Context State Error" completion code. This is as per the spec. However
> HW on receiving the second command additionally marks EP to Flow control
> state in HW which is RTL bug. This bug causes the HW not to respond
> to any further doorbells that are rung by the driver. This makes the EP
> to not functional anymore and causes gross functional failures.
> As a workaround, not to hit this problem, it's better to check the EP state
> and issue a stop EP command only when the EP is in running state.
> As a sidenote, even with this patch there is still a possibility of
> triggering the RTL bug if the context state races with the stop endpoint
> command as described in xHCI spec 4.6.9
> [code simplification and reworded sidenote in commit message -Mathias]
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k at>
> Signed-off-by: Nehal Shah <Nehal-bakulchandra.Shah at>
> Signed-off-by: Mathias Nyman <mathias.nyman at>
> Signed-off-by: Greg Kroah-Hartman <gregkh at>
> BugLink:
> (cherry-picked from commit 28a2369f7d72ece55089f33e7d7b9c1223673cc3)
> Signed-off-by: Alberto Milone <alberto.milone at>

Applied to artful/master-next, thanks.

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