| Message ID | 20250514134011.16285-1-shawn2000100@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | usb: xhci: Set avg_trb_len = 8 for EP0 during Address Device Command | expand |
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index d698095fc88d..fed9e9d1990c 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1166,6 +1166,8 @@ int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *ud ep0_ctx->deq = cpu_to_le64(dev->eps[0].ring->first_seg->dma | dev->eps[0].ring->cycle_state); + ep0_ctx->tx_info |= cpu_to_le32(EP_AVG_TRB_LENGTH(8)); + trace_xhci_setup_addressable_virt_device(dev); /* Steps 7 and 8 were done in xhci_alloc_virt_device() */
According to the xHCI 1.2 spec (Section 6.2.3, p.454), the Average TRB Length (avg_trb_len) for control endpoints should be set to 8. Currently, during the Address Device Command, EP0's avg_trb_len remains 0, which may cause some xHCI hardware to reject the Input Context, resulting in device enumeration failures. In extreme cases, using a zero avg_trb_len in calculations may lead to division-by-zero errors and unexpected system crashes. This patch sets avg_trb_len to 8 for EP0 in xhci_setup_addressable_virt_dev(), ensuring compliance with the spec and improving compatibility across various host controller implementations. Link: https://bugzilla.kernel.org/show_bug.cgi?id=220033 Signed-off-by: jay.chen <shawn2000100@gmail.com> --- drivers/usb/host/xhci-mem.c | 2 ++ 1 file changed, 2 insertions(+)