Re: [PATCH] usb: xhci: add xhci_halt() for HCE Handling

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Jan 28, 2026 at 04:48:49PM +0800, Dayu Jiang wrote:
> On Tue, Jan 27, 2026 at 12:22:40PM +0100, Greg Kroah-Hartman wrote:
> > >  	if (status & STS_HCE) {
> > >  		xhci_warn(xhci, "WARNING: Host Controller Error\n");
> > > +		xhci_halt(xhci);
> > 
> > What is going to start things back up again?  And as you are calling
> > this function, why is the warning message needed anymore?  The
> > tracepoint information will give you that message now, right?
> When HCE is triggered, it indicates a critical hardware failure. 
> Aligning with the handling of HSE (STS_FATAL) by adding 
> xhci_halt() here is more reasonable: without xhci_halt(), the 
> USB controller may fall into an unpredictable and unstable state, 
> which could exacerbate system issues.  
> 
> Retaining the warning message is necessary because it is directly 
> visible in dmesg, whereas tracepoint information requires explicitly 
> enabling xHCI tracepoints. Additionally, if xhci_halt() is called in 
> xhci_irq() without the warning log, it would be impossible to 
> distinguish whether the halt was triggered by HCE or HSE.
> > 
> > And is this just papering over a hardware bug?  Should this really be
> > happening for any normal system?
> Yes, this issue has been reproducible on real-world hardware: HCE is 
> triggered in UAS Storage Device plug/unplug scenarios on Android 
> devices, which enters this error branch and causes an interrupt storm, 
> leading to severe system-level faults.

Great, please provide this information in the changelog text when you
resubmit this, thanks!

greg k-h