Re: [PATCH v2] i2c: omap: Fix standard mode false ACK readings

Andreas Kemnade
2024-09-13T12:09:42Z

Am Wed, 11 Sep 2024 11:40:04 +0200
schrieb "H. Nikolaus Schaller" <hns@goldelico.com>:

> Hi,
>
> > Am 28.04.2023 um 20:30 schrieb Reid Tonking <reidt@ti.com>:
> >
> > On 10:43-20230428, Tony Lindgren wrote:
> >> * Raghavendra, Vignesh <vigneshr@ti.com> [230427 13:18]:
> >>> On 4/27/2023 1:19 AM, Reid Tonking wrote:
> >>>> Using standard mode, rare false ACK responses were appearing with
> >>>> i2cdetect tool. This was happening due to NACK interrupt
> >>>> triggering ISR thread before register access interrupt was
> >>>> ready. Removing the NACK interrupt's ability to trigger ISR
> >>>> thread lets register access ready interrupt do this instead.
> >>
> >> So is it safe to leave NACK interrupt unhandled until we get the
> >> next interrupt, does the ARDY always trigger after hitting this?
> >>
> >> Regards,
> >>
> >> Tony
> >
> > Yep, the ARDY always gets set after a new command when register
> > access is ready so there's no need for NACK interrupt to control
> > this.
>
> I have tested one GTA04A5 board where this patch breaks boot on
> v4.19.283 or v6.11-rc7 (where it was inherited from some earlier -rc
> series).
>
> The device is either stuck with no signs of activity or reports RCU
> stalls after a 20 second pause.
>
cannot reproduce it here. I had a patch to disable 1Ghz on that
device in my tree. Do you have anything strange in your
tree?

Regards,
Andreas