On 29.07.2024 11:21 PM, Dmitry Baryshkov wrote: > On Tue, 30 Jul 2024 at 00:08, Rob Clark <robdclark@xxxxxxxxx> wrote: >> >> On Mon, Jul 29, 2024 at 1:14 PM Dmitry Baryshkov >> <dmitry.baryshkov@xxxxxxxxxx> wrote: >>> >>> On Mon, Jul 29, 2024 at 10:37:48AM GMT, Konrad Dybcio wrote: >>>> From: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> >>>> >>>> SDM845's Adreno SMMU is unique in that it actually advertizes support >>>> for 16K (and 32M) pages, which doesn't hold for newer SoCs. >>>> >>>> This however, seems either broken in the hardware implementation, the >>>> hypervisor middleware that abstracts the SMMU, or there's a bug in the >>>> Linux kernel somewhere down the line that nobody managed to track down. >>>> >>>> Booting SDM845 with 16K page sizes and drm/msm results in: >>>> >>>> *** gpu fault: ttbr0=0000000000000000 iova=000100000000c000 dir=READ >>>> type=TRANSLATION source=CP (0,0,0,0) >>>> >>>> right after loading the firmware. The GPU then starts spitting out >>>> illegal intstruction errors, as it's quite obvious that it got a >>>> bogus pointer. >>>> >>>> Hide 16K support on SDM845's Adreno SMMU to work around this. >>>> >>>> Reported-by: Sumit Semwal <sumit.semwal@xxxxxxxxxx> >>>> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> >>>> --- >>>> There's a mismatch in sender/committer addresses but that's "fine": >>>> https://lore.kernel.org/linux-usb/2024072734-scenic-unwilling-71ea@gregkh/ >>>> --- >>>> drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 10 ++++++++++ >>>> 1 file changed, 10 insertions(+) >>>> >>>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c >>>> index 36c6b36ad4ff..d25825c05817 100644 >>>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c >>>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c >>>> @@ -338,6 +338,15 @@ static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu) >>>> return 0; >>>> } >>>> >>>> +static int qcom_adreno_smmuv2_cfg_probe(struct arm_smmu_device *smmu) >>>> +{ >>>> + /* SDM845 Adreno SMMU advertizes 16K pages support, but something is broken */ >>>> + if (of_device_is_compatible(smmu->dev->of_node, "qcom,sdm845-smmu-v2")) >>>> + smmu->features &= ~ARM_SMMU_FEAT_FMT_AARCH64_16K; >>> >>> Shouldn't we hide that uncoditionally as it's likely that none of v2 >>> Adreno SMMUs support 16k pages? >> >> Hmm, that would be unfortunate to have the GPU not supporting the CPU >> page size. I guess we could still map 16k pages as multiple 4k pages, >> but that is a bit sad.. > > For now this might be limited to older platforms (v2 vs -500) In the commit message: >>>> SDM845's Adreno SMMU is unique in that it actually advertizes support >>>> for 16K (and 32M) pages, which doesn't hold for newer SoCs. Konrad
