Re: [PATCH 4.19 12/81] usb: xhci: wait for CNR controller not ready bit in xhci resume

Hi!

From: Rick Tseng rtseng@nvidia.com

commit a70bcbc322837eda1ab5994d12db941dc9733a7d upstream.

NVIDIA 3.1 xHCI card would lose power when moving power state into D3Cold. Thus we need to wait for CNR bit to clear in xhci resume, just as in xhci init.

...

@@ -1098,6 +1098,18 @@ int xhci_resume(struct xhci_hcd *xhci, b hibernated = true; if (!hibernated) {

• /*
  

•  * Some controllers might lose power during suspend, so wait
  

•  * for controller not ready bit to clear, just as in xHC init.
  

•  */
  

• retval = xhci_handshake(&xhci->op_regs->status,
  

• 			STS_CNR, 0, 10 * 1000 * 1000);
  

• if (retval) {
  

• 	xhci_warn(xhci, "Controller not ready at resume %d\n",
  

• 		  retval);
  

• 	spin_unlock_irq(&xhci->lock);
  

• 	return retval;
  

• }
  

AFAICT if this error happens, xhci will be unusable. So maybe print should be at higher level that warning... that's clearly an error.

Best regards, Pavel