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

[Prashanth K]

On 10-10-23 04:48 pm, Greg Kroah-Hartman wrote:
> On Tue, Oct 10, 2023 at 02:34:44PM +0530, Prashanth K wrote:
> > 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>
>
> No, let us know what kernel version this is to be applied to so we know,
> if you only think this is relevant for 5.15.y as you have tested it
> there, that's fine, I just wanted to be sure.

We tested it on 5.15 for over 20 hours and didn't see any issue. Will 
send a new patch after adding the newline.

Thanks,
Prashanth K