* Re: [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue
2026-03-20 20:12 [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue Pratap Nirujogi
@ 2026-03-20 20:25 ` Andy Shevchenko
2026-03-20 20:32 ` Mario Limonciello (AMD) (kernel.org)
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Andy Shevchenko @ 2026-03-20 20:25 UTC (permalink / raw)
To: Pratap Nirujogi
Cc: andi.shyti, mlimonci, mika.westerberg, jsd, rafael.j.wysocki,
benjamin.chan, bin.du, king.li, linux-i2c, linux-kernel
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
LGTM, assuming that genpd calls are okay,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue
2026-03-20 20:12 [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue Pratap Nirujogi
2026-03-20 20:25 ` Andy Shevchenko
@ 2026-03-20 20:32 ` Mario Limonciello (AMD) (kernel.org)
2026-03-23 5:54 ` Mika Westerberg
2026-03-25 20:17 ` Andi Shyti
3 siblings, 0 replies; 6+ messages in thread
From: Mario Limonciello (AMD) (kernel.org) @ 2026-03-20 20:32 UTC (permalink / raw)
To: Pratap Nirujogi, andi.shyti, andriy.shevchenko, mlimonci,
mika.westerberg, jsd
Cc: rafael.j.wysocki, benjamin.chan, bin.du, king.li, linux-i2c,
linux-kernel
On 3/20/2026 3:12 PM, 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>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
> ---
> Changes v1 -> v2:
>
> * Fixed resume-probe race condition issue
> * Removed NULL check in runtime_resume
> * Updated Fixes tag with appropriate commit
> * Added Signed-off-by for Co-developed-by tag
>
> drivers/i2c/busses/i2c-designware-amdisp.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-amdisp.c b/drivers/i2c/busses/i2c-designware-amdisp.c
> index c48728ad9f6f2..9f0ec0fae6f23 100644
> --- a/drivers/i2c/busses/i2c-designware-amdisp.c
> +++ b/drivers/i2c/busses/i2c-designware-amdisp.c
> @@ -7,6 +7,7 @@
>
> #include <linux/module.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> #include <linux/pm_runtime.h>
> #include <linux/soc/amd/isp4_misc.h>
>
> @@ -76,22 +77,20 @@ static int amd_isp_dw_i2c_plat_probe(struct platform_device *pdev)
>
> device_enable_async_suspend(&pdev->dev);
>
> - pm_runtime_enable(&pdev->dev);
> - pm_runtime_get_sync(&pdev->dev);
> -
> + dev_pm_genpd_resume(&pdev->dev);
> ret = i2c_dw_probe(isp_i2c_dev);
> if (ret) {
> dev_err_probe(&pdev->dev, ret, "i2c_dw_probe failed\n");
> goto error_release_rpm;
> }
> -
> - pm_runtime_put_sync(&pdev->dev);
> + dev_pm_genpd_suspend(&pdev->dev);
> + pm_runtime_set_suspended(&pdev->dev);
> + pm_runtime_enable(&pdev->dev);
>
> return 0;
>
> error_release_rpm:
> amd_isp_dw_i2c_plat_pm_cleanup(isp_i2c_dev);
> - pm_runtime_put_sync(&pdev->dev);
> return ret;
> }
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue
2026-03-20 20:12 [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue Pratap Nirujogi
2026-03-20 20:25 ` Andy Shevchenko
2026-03-20 20:32 ` Mario Limonciello (AMD) (kernel.org)
@ 2026-03-23 5:54 ` Mika Westerberg
2026-03-25 20:17 ` Andi Shyti
3 siblings, 0 replies; 6+ messages in thread
From: Mika Westerberg @ 2026-03-23 5:54 UTC (permalink / raw)
To: Pratap Nirujogi
Cc: andi.shyti, andriy.shevchenko, mlimonci, jsd, rafael.j.wysocki,
benjamin.chan, bin.du, king.li, linux-i2c, linux-kernel
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>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue
2026-03-20 20:12 [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue Pratap Nirujogi
` (2 preceding siblings ...)
2026-03-23 5:54 ` Mika Westerberg
@ 2026-03-25 20:17 ` Andi Shyti
2026-03-25 20:36 ` Nirujogi, Pratap
3 siblings, 1 reply; 6+ messages in thread
From: Andi Shyti @ 2026-03-25 20:17 UTC (permalink / raw)
To: Pratap Nirujogi
Cc: andriy.shevchenko, mlimonci, mika.westerberg, jsd,
rafael.j.wysocki, benjamin.chan, bin.du, king.li, linux-i2c,
linux-kernel
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
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] i2c: designware: amdisp: Fix resume-probe race condition issue
2026-03-25 20:17 ` Andi Shyti
@ 2026-03-25 20:36 ` Nirujogi, Pratap
0 siblings, 0 replies; 6+ messages in thread
From: Nirujogi, Pratap @ 2026-03-25 20:36 UTC (permalink / raw)
To: Andi Shyti, Pratap Nirujogi
Cc: andriy.shevchenko, mlimonci, mika.westerberg, jsd,
rafael.j.wysocki, benjamin.chan, bin.du, king.li, linux-i2c,
linux-kernel
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@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
^ permalink raw reply [flat|nested] 6+ messages in thread