On 11/5/2024 7:43 PM, Alan Stern wrote:
On Tue, Nov 05, 2024 at 02:48:50PM +0530, Raju Rangoju wrote:
During the High-Speed Isochronous Audio transfers, xHCI
controller on certain AMD platforms experiences momentary data
loss. This results in Missed Service Errors (MSE) being
generated by the xHCI.
The root cause of the MSE is attributed to the ISOC OUT endpoint
being omitted from scheduling. This can happen either when an IN
endpoint with a 64ms service interval is pre-scheduled prior to
the ISOC OUT endpoint or when the interval of the ISOC OUT
endpoint is shorter than that of the IN endpoint. Consequently,
the OUT service is neglected when an IN endpoint with a service
interval exceeding 32ms is scheduled concurrently (every 64ms in
this scenario).
This issue is particularly seen on certain older AMD platforms.
To mitigate this problem, it is recommended to adjust the service
interval of the IN endpoint to exceed 32ms (interval 8). This
Do you mean "not to exceed 32 ms"?
adjustment ensures that the OUT endpoint will not be bypassed,
even if a smaller interval value is utilized.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Raju Rangoju <Raju.Rangoju@xxxxxxx>
---
drivers/usb/host/xhci-mem.c | 5 +++++
drivers/usb/host/xhci-pci.c | 14 ++++++++++++++
drivers/usb/host/xhci.h | 1 +
3 files changed, 20 insertions(+)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index d2900197a49e..4892bb9afa6e 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1426,6 +1426,11 @@ int xhci_endpoint_init(struct xhci_hcd *xhci,
/* Periodic endpoint bInterval limit quirk */
if (usb_endpoint_xfer_int(&ep->desc) ||
usb_endpoint_xfer_isoc(&ep->desc)) {
+ if ((xhci->quirks & XHCI_LIMIT_ENDPOINT_INTERVAL_9) &&
+ usb_endpoint_xfer_int(&ep->desc) &&
+ interval >= 9) {
+ interval = 8;
+ }
This change ensures that the interval is <= 32 ms.
That's correct, thanks for pointing it out. I'll take care of this in V2.
Alan Stern
