linux-kernel - Re: [PATCH] soc: qcom: ice: Avoid probe deferring for un-supported ICE feature

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Message-ID: <ef1611c9-4698-45ed-8ccc-fbad42acd8da@oss.qualcomm.com>
Date: Fri, 30 Jan 2026 13:36:28 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Sumit Garg <sumit.garg@...nel.org>
Cc: Rob Herring <robh+dt@...nel.org>, linux-arm-msm@...r.kernel.org,
        andersson@...nel.org, konradybcio@...nel.org, abelvesa@...nel.org,
        mani@...nel.org, linux-kernel@...r.kernel.org,
        Sumit Garg <sumit.garg@....qualcomm.com>
Subject: Re: [PATCH] soc: qcom: ice: Avoid probe deferring for un-supported
 ICE feature

On 1/30/26 1:29 PM, Sumit Garg wrote:
> On Fri, Jan 30, 2026 at 12:55:53PM +0100, Konrad Dybcio wrote:
>> On 1/30/26 12:36 PM, Sumit Garg wrote:
>>> On Fri, Jan 30, 2026 at 10:59:18AM +0100, Konrad Dybcio wrote:
>>>> On 1/30/26 10:52 AM, Sumit Garg wrote:
>>>>> On Fri, Jan 30, 2026 at 10:34:26AM +0100, Konrad Dybcio wrote:
>>>>>> On 1/30/26 10:11 AM, Sumit Garg wrote:
>>>>>>> From: Sumit Garg <sumit.garg@....qualcomm.com>
>>
>> [...]
>>
>>>>> Since qcom,ufs depends on qcom,ice via a phandle, so isn't the probe
>>>>> orderering automatically taken care off? Or that isn't the case here?
>>>>
>>>> No, that's guaranteed by devlink only with certain properties.
>>>
>>> Okay I see. The other alternate solution I can come up is following to
>>> keep the deferred probing intact. Let me know your thoughts on this:
>>>
>>> diff --git a/drivers/soc/qcom/ice.c b/drivers/soc/qcom/ice.c
>>> index ab9586b8caf5..76bf9f94fbaf 100644
>>> --- a/drivers/soc/qcom/ice.c
>>> +++ b/drivers/soc/qcom/ice.c
>>> @@ -559,7 +559,7 @@ static struct qcom_ice *qcom_ice_create(struct device *dev,
>>>
>>>         if (!qcom_scm_ice_available()) {
>>>                 dev_warn(dev, "ICE SCM interface not found\n");
>>> -               return NULL;
>>> +               return ERR_PTR(-ENODEV);
>>>         }
>>>
>>>         engine = devm_kzalloc(dev, sizeof(*engine), GFP_KERNEL);
>>> @@ -648,11 +648,14 @@ static struct qcom_ice *of_qcom_ice_get(struct device *dev)
>>>         }
>>>
>>>         ice = platform_get_drvdata(pdev);
>>> -       if (!ice) {
>>> +       if (IS_ERR_OR_NULL(ice)) {
>>>                 dev_err(dev, "Cannot get ice instance from %s\n",
>>>                         dev_name(&pdev->dev));
>>>                 platform_device_put(pdev);
>>> -               return NULL;
>>> +               if (PTR_ERR(ice) == -ENODEV)
>>> +                       return NULL;
>>> +               else
>>> +                       return ERR_PTR(-EPROBE_DEFER);
>>>         }
>>>
>>>         link = device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
>>> @@ -726,7 +729,7 @@ static int qcom_ice_probe(struct platform_device *pdev)
>>>         }
>>>
>>>         engine = qcom_ice_create(&pdev->dev, base);
>>> -       if (IS_ERR(engine))
>>> +       if (IS_ERR(engine) && PTR_ERR(engine) != -ENODEV)
>>>                 return PTR_ERR(engine);
>>>
>>>         platform_set_drvdata(pdev, engine);
>>
>> This looks more robust. Although the UFS and MMC drivers today check
>> for EOPNOTSUPP, so perhaps throwing that would be even better
> 
> Sure, I can use that error code instead.
> 
>>
>>>
>>>> In this case though, I think it could make sense to add it to the
>>>> "suppliers" list in drivers/of/property.c.
>>>>
>>>> I don't know if vendors adding their custom properties there is a
>>>> pattern that +Rob will be happy about though..
>>>
>>> Not sure if that's a shorter path as I would like to see fix for this
>>> issue backported as well.
>>>
>>> Aside, not sure how much stable ICE feature itself is as I got following
>>> crash with QLI boot firmware on Kodiak:
>>>
>>> [    5.172970] SError Interrupt on CPU6, code 0x00000000be000000 -- SError
>>> [    5.172986] CPU: 6 UID: 0 PID: 241 Comm: (udev-worker) Tainted: G   M                6.19.0-rc5-next-20260115-gc1a0fee87a05 #9 PREEMPT 
>>> [    5.172996] Tainted: [M]=MACHINE_CHECK
>>> [    5.172999] Hardware name: Qualcomm Technologies, Inc. Robotics RB3gen2 (DT)
>>> [    5.173003] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>>> [    5.173010] pc : qcom_ice_create.part.0+0x6c/0x24c [qcom_ice]
>>> [    5.173024] lr : qcom_ice_create.part.0+0xe4/0x24c [qcom_ice]
>>
>> Could you please decode the pc value with ./scripts/faddr2line?
>> My compiler produces different output
>>
>> ./scripts/faddr2line vmlinux(or path to .ko) <symbol_name>
>>
> 
> This points at:
> 
> static bool qcom_ice_check_supported(struct qcom_ice *ice)
> {
> -->   u32 regval = qcom_ice_readl(ice, QCOM_ICE_REG_VERSION);
> 
> $ ./scripts/faddr2line ./drivers/soc/qcom/qcom_ice.ko qcom_ice_create.part.0+0x6c/0x24c
> qcom_ice_create.part.0+0x6c/0x24c:
> readl at /home/sumit/build/upstream/linux/./include/asm-generic/io.h:232 (discriminator 1)
> (inlined by) qcom_ice_check_supported at /home/sumit/build/upstream/linux/drivers/soc/qcom/ice.c:118 (discriminator 1)
> (inlined by) qcom_ice_create at /home/sumit/build/upstream/linux/drivers/soc/qcom/ice.c:587 (discriminator 1)
> 
> To me it looks like an issue related to access control policy. Note that
> it's the Gunyah based stack only where this issue is seen.

Please first check if that's not just a lack of power, because apparently
we never guaranteed that would be present, see:

https://lore.kernel.org/linux-arm-msm/20260123-qcom_ice_power_and_clk_vote-v1-0-e9059776f85c@qti.qualcomm.com/

https://lore.kernel.org/linux-arm-msm/20260123-enable-ufs-ice-clock-scaling-v3-0-d0d8532abd98@oss.qualcomm.com/

Konrad