Re: [PATCH RESEND] xhci: Keep interrupt disabled in initialization until host is running.

[Prashanth K]

On 09-10-23 06:22 pm, Greg Kroah-Hartman wrote:
> On Mon, Oct 09, 2023 at 04:09:26PM +0530, Prashanth K wrote:
> > From: Hongyu Xie <xy521521@xxxxxxxxx>
> >
> > [ Upstream commit a808925075fb750804a60ff0710614466c396db4 ]
> >
> > irq is disabled in xhci_quiesce(called by xhci_halt, with bit:2 cleared
> > in USBCMD register), but xhci_run(called by usb_add_hcd) re-enable it.
> > It's possible that you will receive thousands of interrupt requests
> > after initialization for 2.0 roothub. And you will get a lot of
> > warning like, "xHCI dying, ignoring interrupt. Shouldn't IRQs be
> > disabled?". This amount of interrupt requests will cause the entire
> > system to freeze.
> > This problem was first found on a device with ASM2142 host controller
> > on it.
> >
> > [tidy up old code while moving it, reword header -Mathias]
> >
> > Cc: stable@xxxxxxxxxx
> > Signed-off-by: Hongyu Xie <xiehongyu1@xxxxxxxxxx>
> > Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20220623111945.1557702-2-mathias.nyman@xxxxxxxxxxxxxxx
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx> # 5.15
> > Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
> > ---
>
> Any specific reason you missed adding the extra blank line in this
> version of the backport that the original added?  That is going to cause
> problems in the future if other patches are added on top of this that
> would be expecting it because it is that way in Linus's tree.

Thanks for pointing out, i removed it while resolving some merge 
conflicts. Will add it back in next version.

> And why is this only relevant for 5.15.y?

I'm not really sure why this was only ported from 5.19 onwards and not 
present in older kernels (could be because of dependencies/conflicts).

But anyways im backporting it to 5.15 since an irq storm was seen on a 
qcom SOC working on 5.15, and this patch is helping solve it.

Should I change the CC to just stable kernel (without mentioning kernel 
version) ?
something like this -- Cc: <stable@xxxxxxxxxxxxxxx>

Regards.
Prashanth K