Re: [PATCH] usb: xhci: fix maximum event ring segments calculation

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 8/31/26 09:55, Thorsten Leemhuis wrote:
> On 8/30/26 05:12, Pierre-David Belanger wrote:
> 
>> The failure on 08dbfad3f504:
>>
>>    xhci_hcd 0000:00:04.0: xHCI Host Controller
>>    xhci_hcd 0000:00:04.0: new USB bus registered, assigned bus number 1
>>    xhci_hcd 0000:00:04.0: Failed to allocate interrupter erst
>>    xhci_hcd 0000:00:04.0: can't setup: -12
>>    xhci_hcd 0000:00:04.0: USB bus 1 deregistered
>>    xhci_hcd 0000:00:04.0: init 0000:00:04.0 fail, -12
>>    xhci_hcd 0000:00:04.0: probe with driver xhci_hcd failed with error -12
> FWIW, not my area of expertise, but to me it looks like there were two
> similar fixes submitted earlier to address this and "usb: xhci: Fix
> HCS_ERST_MAX conversion" (
> https://lore.kernel.org/all/20260828105926.930033-1-oushixiong1025@163.com/
> ) seems to be heading towards mainline already according to Mathias.
> Sadly this missed -rc1, wonder why it wasn't submitted for it to prevent
> more people from running into this, but whatever, that's ship has sailed.

Looks like at least QEMU and Mediatek users were hit by this issue.

Note that this is a v7.3-rc1 regression which was found during merge window for v7.3-rc1.
v7.3-rc1 came out a few hours ago.
I can't resolve it much earlier than this.

Thanks
Mathias