Re: [PATCH V7 2/4] iommu/arm-smmu-v3: Add device-tree support for CMDQV driver

[Jon Hunter]

On 07/01/2026 06:44, Ashish Mhetre wrote:
> On 12/20/2025 12:19 AM, Nicolin Chen wrote:
> > On Fri, Dec 19, 2025 at 10:48:22AM +0000, Jon Hunter wrote:
> > > On 18/12/2025 18:57, Nicolin Chen wrote:
> > > > On Thu, Dec 18, 2025 at 08:48:32AM +0000, Jon Hunter wrote:
> > > > > On 18/12/2025 06:32, Ashish Mhetre wrote:
> > > > > > On 12/18/2025 2:13 AM, Jon Hunter wrote:
> > > > > > > > +    smmu->impl_dev = &pdev->dev;
> > > > > > > > +    smmu->options |= ARM_SMMU_OPT_TEGRA241_CMDQV;
> > > > > > > > +    dev_info(smmu->dev, "found companion CMDQV device: %s\n",
> > > > > > > > +         dev_name(smmu->impl_dev));
> > > > > > > This seems a bit noisy. dev_dbg?
> > > > > > This info print is similar to what is there in ACPI path as well.
> > > > > > It's only a single print per SMMU at boot time. Should I still change
> > > > > > it to dev_dbg?
> > > > > Yes, I would.
> > > > It's really not that bad IMHO, I am not against that though..
> > > >
> > > > If we have to change that, we'd need another patch changing the
> > > > one in the ACPI path as well to keep things aligned.
> > > Regardless of what is already present, does not mean we need add more 
> > > prints
> > > to just say everything is OK.
> > This is how it looks like for each instance probe():
> >
> > [    2.709269] arm-smmu-v3 arm-smmu-v3.10.auto: found companion CMDQV 
> > device: NVDA200C:00
> > [    2.709273] arm-smmu-v3 arm-smmu-v3.10.auto: option mask 0x10
> > [    2.709618] arm-smmu-v3 arm-smmu-v3.10.auto: ias 48-bit, oas 48-bit 
> > (features 0x001e1fbf)
> > [    2.716236] arm-smmu-v3 arm-smmu-v3.10.auto: allocated 524288 
> > entries for cmdq
> > [    2.719432] arm-smmu-v3 arm-smmu-v3.10.auto: allocated 524288 
> > entries for evtq
> > [    2.725898] arm-smmu-v3 arm-smmu-v3.10.auto: allocated 524288 
> > entries for priq
> > [    2.736051] arm-smmu-v3 arm-smmu-v3.10.auto: allocated 524288 
> > entries for vcmdq0
> > [    2.742553] arm-smmu-v3 arm-smmu-v3.10.auto: allocated 524288 
> > entries for vcmdq1
> > [    2.742586] arm-smmu-v3 arm-smmu-v3.10.auto: msi_domain absent - 
> > falling back to wired irqs
> > [    2.742759] arm-smmu-v3 arm-smmu-v3.10.auto: no priq irq - PRI will 
> > be broken
> >
> > On a second thought: The CMDQV device has a very unclear naming in
> > ACPI path: "NVDA200C:00". So, printing it gives us a hint for any
> > later warning/error tagged with "NVDA200C:00".
> >
> > Now, for DT, it might be okay to not print it. But making the two
> > paths asymmetric feels odd. So, is it really worth nitpicking here
> > given that each SMMU already prints quite a few lines on probe()?
> >
> > Nicolin
>
> Hi Jon, Nic,
>
> Shall I keep this print or send a new version removing it?

Make it dev_dbg() and you can always enable it if you want it. 99.9% of 
the time you will not need this.

Thanks!
Jon

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nvpublic