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

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Message-ID: <aXykJIuEwbeWuhs5@sumit-xelite>
Date: Fri, 30 Jan 2026 17:59:24 +0530
From: Sumit Garg <sumit.garg@...nel.org>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
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 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.

-Sumit