linux-kernel - Re: [PATCH v5] iommu/arm-smmu-qcom: add actlr settings for mdss on Qualcomm platforms

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Message-ID: <b0a39971-5616-4768-b08f-b359cabd2f6e@oss.qualcomm.com>
Date: Fri, 9 Jan 2026 16:59:13 +0530
From: Bibek Kumar Patro <bibek.patro@....qualcomm.com>
To: Will Deacon <will@...nel.org>, konrad.dybcio@....qualcomm.com,
        robin.clark@....qualcomm.com, dmitry.baryshkov@....qualcomm.com,
        robin.murphy@....com, joro@...tes.org
Cc: catalin.marinas@....com, kernel-team@...roid.com, iommu@...ts.linux.dev,
        linux-arm-msm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Charan Teja Kalla <charan.kalla@....qualcomm.com>
Subject: Re: [PATCH v5] iommu/arm-smmu-qcom: add actlr settings for mdss on
 Qualcomm platforms



On 1/6/2026 4:28 AM, Will Deacon wrote:
> On Tue, 09 Dec 2025 10:53:23 +0530, bibek.patro@....qualcomm.com wrote:
>> Add ACTLR settings for missing MDSS devices on Qualcomm platforms.
>>
>> These are QoS settings and are specific to per SoC thus different
>> settings, eg: some have shallow prefetch while others have no
>> prefetch.
>>
>> Aswell, this prefetch feature is not implemented for all the
>> platforms, capturing to those are implemented to the best of my
>> knowledge.
>>
>> [...]
> 
> Applied to iommu (arm/smmu/updates), thanks!
> 

Hi Will,

While reviewing the applied patch, I noticed that during the transition 
from v2 [1] to v3 [2], one of the SoC entries (sa8775p) appears to have 
been dropped while addressing the review comments.

Sorry for not catching this earlier.

Would it be acceptable at this stage to send a v6 including the diff below?
Alternatively, if it’s easier on your side, please feel free to squash 
this into the existing patch currently applied in your tree.

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c 
b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 456d5146831e..718d102356d9 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -43,6 +43,8 @@ static const struct of_device_id 
qcom_smmu_actlr_client_of_match[] = {
                         .data = (const void *) (PREFETCH_DEEP | CPRE | 
CMTLB) },
         { .compatible = "qcom,qcm2290-mdss",
                         .data = (const void *) (PREFETCH_SHALLOW | CPRE 
| CMTLB) },
+       { .compatible = "qcom,sa8775p-mdss",
+                       .data = (const void *) (PREFETCH_DEFAULT | CMTLB) },
         { .compatible = "qcom,sc7280-mdss",
                         .data = (const void *) (PREFETCH_SHALLOW | CPRE 
| CMTLB) },
         { .compatible = "qcom,sc7280-venus",

If neither approach looks suitable, I can send a standalone follow‑up 
patch, either on top of your tree[3] or on tip.

[1]: 
https://lore.kernel.org/lkml/20251118171822.3539062-1-charan.kalla@oss.qualcomm.com/#t
[2]: 
https://lore.kernel.org/all/20251124171030.323989-1-charan.kalla@oss.qualcomm.com/
[3]: 
https://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git/log/?h=arm/smmu/updates

Thanks & regards,
Bibek


> [1/1] iommu/arm-smmu-qcom: Add actlr settings for mdss on Qualcomm platforms
>        https://git.kernel.org/iommu/c/f91879fdf70b
> 
> Cheers,