Re: [PATCH 0/4] iommu: tegra-gart cleanups

[Robin Murphy <robin.murphy@arm.com>]

On 2023-05-16 13:16, Nicolas Chauvet wrote:
> Le mar. 16 mai 2023 à 13:45, Robin Murphy <robin.murphy@arm.com> a écrit :
>>
>> On 2023-05-16 10:53, Nicolas Chauvet wrote:
> ...
>>> For what it worth, I've tried to test this serie with "grate patches"
>>> (1) rebased on top on 6.4-rc2, that would make use of the tegra-gart.
>>> That was on PAZ00 (with only 512M of RAM and 96M CMA still allocated).
>>> Unfortunately, this lead to the following errors with display problems
>>> (no character displayed in lxt-terminal and etc)
>>
>> Thanks for testing - it's quite possible I've made a silly mistake
>> somewhere, but just to double-check, does the same happen with the
>> existing driver if you boot with "tegra-gart.gart_debug=1" (or at least
>> enable the parameter via sysfs before the DRM driver gets going)?
> 
> Using echo 1 > /sys/module/tegra_gart/parameters/gart_debug shows the
> same messages and the same artefacts (missing refreshed window
> content).
> Using "echo 0 > /sys/module/tegra_gart/parameters/gart_debug" revert
> back to normal...

OK, cool, so it looks like a pre-existing bug in the caller, but I guess 
it does mean that unconditionally enabling the checks isn't ideal until 
that can be sorted out.

Thanks,
Robin.

> [ 7661.026139] tegra-mc 7000f000.memory-controller: gart: Page entry is in-use
> [ 7661.033189] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> mapping failed 4294967274 262144
> [ 7661.042197] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> failed size 262144: -12
> [ 7661.589552] tegra-mc 7000f000.memory-controller: gart: Page entry is in-use
> [ 7661.596690] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> mapping failed 4294967274 262144
> [ 7661.605865] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> failed size 262144: -12
> [ 7662.078823] tegra-mc 7000f000.memory-controller: gart: Page entry is in-use
> [ 7662.085987] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> mapping failed 4294967274 262144
> [ 7662.095137] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> failed size 262144: -12
> [ 7662.123677] tegra-mc 7000f000.memory-controller: gart: Page entry is in-use
> [ 7662.130758] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> mapping failed 4294967274 262144
> [ 7662.140100] [drm:tegra_bo_gart_map_locked [tegra_drm]] *ERROR*
> failed size 262144: -12