Commit 7acaef4f authored by Konrad Dybcio's avatar Konrad Dybcio Committed by Greg Kroah-Hartman
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iommu/arm-smmu-qcom: Work around SDM845 Adreno SMMU w/ 16K pages



[ Upstream commit 2d42d3ba ]

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.

Moreover, it seems like this issue also concerns other implementations
of SMMUv2 on Qualcomm SoCs, such as the one on SC7180.

Hide 16K support on such instances to work around this.

Reported-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: default avatarKonrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240824-topic-845_gpu_smmu-v2-1-a302b8acc052@quicinc.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
Stable-dep-of: 19eb465c ("iommu/arm-smmu-qcom: apply num_context_bank fixes for SDM630 / SDM660")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 324e1ec4
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