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. The above bug causes the HW not to respond
to any further doorbells that are rung by the driver. This causes the EP
to not functional anymore and causes gross functional failures.
As a workaround, not to hit this problem, its better we check the EP state
and issue the stop EP command only when the EP is in running state.
Signed-off-by: Shyam Sundar S K <shyam-sundar....@amd.com>
Signed-off-by: Nehal Shah <nehal-bakulchandra.s...@amd.com>
---
drivers/usb/host/xhci-hub.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 0dde49c..5fa3a57 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -398,17 +398,26 @@ static int xhci_stop_device(struct xhci_hcd *xhci, int
slot_id, int suspend)
spin_lock_irqsave(&xhci->lock, flags);
for (i = LAST_EP_INDEX; i > 0; i--) {
if (virt_dev->eps[i].ring && virt_dev->eps[i].ring->dequeue) {
- struct xhci_command *command;
- command = xhci_alloc_command(xhci, false, false,
- GFP_NOWAIT);
- if (!command) {
- spin_unlock_irqrestore(&xhci->lock, flags);
- xhci_free_command(xhci, cmd);
- return -ENOMEM;
+ //get the output EP context and stop only those EP
+ // which are running
+ struct xhci_ep_ctx *ep_ctx;
+
+ ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->out_ctx, i);
+
+ if (GET_EP_CTX_STATE(ep_ctx) == EP_STATE_RUNNING) {
+ struct xhci_command *command;
+ command = xhci_alloc_command(xhci, false, false,
+ GFP_NOWAIT);
+ if (!command) {
+ spin_unlock_irqrestore(&xhci->lock,
+ flags);
+ xhci_free_command(xhci, cmd);
+ return -ENOMEM;
+ }
+ xhci_queue_stop_endpoint(xhci, command,
+ slot_id, i, suspend);
}
- xhci_queue_stop_endpoint(xhci, command, slot_id, i,
- suspend);
}
}
xhci_queue_stop_endpoint(xhci, cmd, slot_id, 0, suspend);
--
2.7.4
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