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? > + > + return 0; > +} > + > static void qcom_smmu_write_s2cr(struct arm_smmu_device *smmu, int idx) > { > struct arm_smmu_s2cr *s2cr = smmu->s2crs + idx; > @@ -436,6 +445,7 @@ static const struct arm_smmu_impl sdm845_smmu_500_impl = { > > static const struct arm_smmu_impl qcom_adreno_smmu_v2_impl = { > .init_context = qcom_adreno_smmu_init_context, > + .cfg_probe = qcom_adreno_smmuv2_cfg_probe, > .def_domain_type = qcom_smmu_def_domain_type, > .alloc_context_bank = qcom_adreno_smmu_alloc_context_bank, > .write_sctlr = qcom_adreno_smmu_write_sctlr, > > --- > base-commit: 931a3b3bccc96e7708c82b30b2b5fa82dfd04890 > change-id: 20240726-topic-845_gpu_smmu-ab738f7a013c > > Best regards, > -- > Konrad Dybcio <konradybcio@xxxxxxxxxx> > -- With best wishes Dmitry
