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

[Mika Westerberg]

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>

Acked-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>