Re: [PATCH v2 08/34] drm/msm: Remove vram carveout support

[Luca Weiss]

On Thu Apr 17, 2025 at 1:20 AM CEST, Dmitry Baryshkov wrote:
> On Wed, Mar 19, 2025 at 07:52:20AM -0700, Rob Clark wrote:
>> From: Rob Clark <robdclark@xxxxxxxxxxxx>
>> 
>> It is standing in the way of drm_gpuvm / VM_BIND support.  Not to
>> mention frequently broken and rarely tested.  And I think only needed
>> for a 10yr old not quite upstream SoC (msm8974).
>
> Well... MSM8974 is quite upstream, but anyway, let's drop it. Maybe
> somebody will write an IOMMU driver.

msm8226 is also using this!

Sad to see this happening, but I get the reasoning. Unfortunately nobody
who really knows GPU and IOMMU bits has looked at this in recent years,
for msm8974 we (mostly Matti Lehtimäki and me) have a semi-working
branch but hitting random issues with it.

Would've been nice if somebody made functional IOMMU support back in
like 2015-2016 when more people looked at this platform.

Regards
Luca

>
>> 
>> Maybe we can add support back in later, but I'm doubtful.
>> 
>> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/msm/adreno/a2xx_gpu.c      |   6 +-
>>  drivers/gpu/drm/msm/adreno/a3xx_gpu.c      |  13 +-
>>  drivers/gpu/drm/msm/adreno/a4xx_gpu.c      |  13 +-
>>  drivers/gpu/drm/msm/adreno/adreno_device.c |   4 -
>>  drivers/gpu/drm/msm/adreno/adreno_gpu.h    |   1 -
>>  drivers/gpu/drm/msm/msm_drv.c              | 117 +-----------------
>>  drivers/gpu/drm/msm/msm_drv.h              |  11 --
>>  drivers/gpu/drm/msm/msm_gem.c              | 131 ++-------------------
>>  drivers/gpu/drm/msm/msm_gem.h              |   5 -
>>  drivers/gpu/drm/msm/msm_gem_submit.c       |   5 -
>>  10 files changed, 19 insertions(+), 287 deletions(-)