Re: [REGRESSION] EMEM address decode error when using Tegra210 media engines

[Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>]

On 6/3/25 4:32 PM, Jason Gunthorpe wrote:
> On Tue, Jun 03, 2025 at 04:06:47PM +0100, Diogo Ivo wrote:
>> Hello,
>>
>> Commit 50568f87d1e233e introduced a regression when trying to use the media
>> accelerators present on the Tegra X1 SoC.
>>
>> I came across this regression when testing the branch [1] that leverages
>> the NVJPG engine in the Tegra X1 for decoding a JPEG file. After commit
>> 50568f87d1e233e we see the following error messages after submitting a job
>> through the TEGRA_CHANNEL_SUBMIT IOCTL:
> 
> Maybe this?
> 
> @@ -567,7 +567,7 @@ static void tegra_smmu_set_pde(struct tegra_smmu_as *as, unsigned long iova,
>   
>          /* The flush the page directory entry from caches */
>          dma_sync_single_range_for_device(smmu->dev, as->pd_dma, offset,
> -                                        sizeof(*pd), DMA_TO_DEVICE);
> +                                        sizeof(pd->val[0]), DMA_TO_DEVICE);
>   
>          /* And flush the iommu */
>          smmu_flush_ptc(smmu, as->pd_dma, offset);
> 
> It is the only mistake I was able to notice.
> 
> But I'd be puzzled - I'd expect bigger sizeof would make it slower not
> broken.. Though your crash sure looks like either missing cache
> coherency or a bad PTE construction.
> 

With this change there is still an error:

[   21.794016] tegra-mc 70019000.memory-controller: nvjpgsrd: read 
@0x00000000ffffbe00: EMEM address decode error (SMMU translation error 
[--S])
[   21.804409] tegra-mc 70019000.memory-controller: nvjpgsrd: read 
@0x00000000ffffbe00: Page fault (SMMU translation error [--S])

the difference being that we only get it for one address compared to the
previous log.

Diogo