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

[Dayu Jiang]

Hi Greg,

I have updated the changelog text as requested and resubmitted the patch.
https://lore.kernel.org/linux-usb/20260128100746.561626-1-jiangdayu@xxxxxxxxxx/
Please kindly review it and let me know if it is acceptable now.

Thanks,
Dayu Jiang

On Wed, Jan 28, 2026 at 09:56:18AM +0100, Greg Kroah-Hartman wrote:
> 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