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

["Nirujogi, Pratap" <pnirujog@amd.com>]

On 3/25/2026 4:17 PM, Andi Shyti wrote:
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> 
> 
> 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@amd.com>
>> Signed-off-by: Bin Du <bin.du@amd.com>
>> Signed-off-by: Pratap Nirujogi <pratap.nirujogi@amd.com>
> 
> merged to i2c/i2c-host-fixes.
> 
Thanks Andi.

> Thanks,
> Andi