Re: [PATCH v3 1/3] drm/vc4: Remove the need for the GPU-subsystem DT node.

[Eric Anholt]

Rob Herring <robh+dt@xxxxxxxxxx> writes:

> On Mon, Apr 16, 2018 at 5:52 PM, Eric Anholt <eric@xxxxxxxxxx> wrote:
>> The GPU subsystem node was a workaround to have a central device to
>> bind V3D and display to.  Following the lead of 246774d17fc0
>> ("drm/etnaviv: remove the need for a gpu-subsystem DT node"), remove
>> the subsystem node usage and just create a platform device for the DRM
>> device to attach to if any of the subsystem devices are present.
>>
>> v2: Simplify the DT walking code.
>> v3: Always put the node.
>>
>> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
>> ---
>>  .../bindings/display/brcm,bcm-vc4.txt         |  7 -----
>>  drivers/gpu/drm/vc4/vc4_drv.c                 | 28 +++++++++++++------
>>  drivers/gpu/drm/vc4/vc4_hvs.c                 |  1 +
>>  drivers/gpu/drm/vc4/vc4_v3d.c                 |  1 +
>>  4 files changed, 22 insertions(+), 15 deletions(-)
>
> Reviewed-by: Rob Herring <robh@xxxxxxxxxx>

Unfortunately, on further testing, this ends up broken.  My guess is
that our new platform device isn't on the same bus, so we don't get our
dma-ranges translation when we use drm->dev, and that breaks caching
behavior.

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