Re: [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue

[Nirujogi, Pratap]

On 3/25/2026 4:17 PM, Andi Shyti wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> Hi Pratap,
>
> On Fri, Mar 20, 2026 at 04:12:22PM -0400, Pratap Nirujogi wrote:
> > Identified resume-probe race condition in kernel v7.0 with the commit
> > 38fa29b01a6a ("i2c: designware: Combine the init functions"),but this
> > issue existed from the beginning though not detected.
> >
> > The amdisp i2c device requires ISP to be in power-on state for probe
> > to succeed. To meet this requirement, this device is added to genpd
> > to control ISP power using runtime PM. The pm_runtime_get_sync() called
> > before i2c_dw_probe() triggers PM resume, which powers on ISP and also
> > invokes the amdisp i2c runtime resume before the probe completes resulting
> > in this race condition and a NULL dereferencing issue in v7.0
> >
> > Fix this race condition by using the genpd APIs directly during probe:
> >    - Call dev_pm_genpd_resume() to Power ON ISP before probe
> >    - Call dev_pm_genpd_suspend() to Power OFF ISP after probe
> >    - Set the device to suspended state with pm_runtime_set_suspended()
> >    - Enable runtime PM only after the device is fully initialized
> >
> > Fixes: d6263c468a761 ("i2c: amd-isp: Add ISP i2c-designware driver")
> > Co-developed-by: Bin Du <bin.du@xxxxxxx>
> > Signed-off-by: Bin Du <bin.du@xxxxxxx>
> > Signed-off-by: Pratap Nirujogi <pratap.nirujogi@xxxxxxx>
>
> merged to i2c/i2c-host-fixes.
Thanks Andi.

> Thanks,
> Andi