[RFC PATCH 0/2] drm: etnaviv: Unmap gems on gem_close

[Guido Günther]

Hi,
On Thu, Oct 29, 2020 at 03:08:09PM +0100, Daniel Vetter wrote:
> On Thu, Oct 29, 2020 at 2:54 PM Guido Günther <agx at sigxcpu.org> wrote:
> >
> > This is meant as a RFC since i'm not sure if this is the right
> > way to fix the problem:
> >
> > So far the unmap from gpu address space only happened when dropping the
> > last ref in gem_free_object_unlocked, however that is skipped if there's
> > still multiple handles to the same GEM object.
> >
> > Since userspace (here mesa) in the case of softpin hands back the memory
> > region to the pool of available GPU virtual memory closing the handle
> > via DRM_IOCTL_GEM_CLOSE this can lead to etnaviv_iommu_insert_exact
> > failing later since userspace thinks the vaddr is available while the
> > kernel thinks it isn't making the submit fail like
> >
> >      [E] submit failed: -14 (No space left on device) (etna_cmd_stream_flush:244)
> >
> > Fix this by unmapping the memory via the .gem_close_object callback.
> >
> > The patch is against 5.9 and will need to be redone for drm-misc-next due to
> > the conversion to GEM object functions but i'm happy to do that it looks like
> > the right approach.
> >
> > I can trigger the problem when plugging/unplugging a DP screen driven by DCSS
> > while DSI is driven by mxsfb. It preferably happens with 4k since this
> > allocates bigger chunks.
> >
> > I also folded in a commit checking for the context->lock in
> > etnaviv_iommu_insert_exact and etnaviv_iommu_remove_mapping too to make it
> > match etnaviv_iommu_find_iova.
> >
> > Guido Günther (2):
> >   drm: etnaviv: Add lockdep annotations for context lock
> >   drm: etnaviv: Unmap gems on gem_close
> 
> Can you pls resubmit with dri-devel on cc? This is kinda a general
> problem of letting userspace manage the gpu VA.

Sure, done.
 -- Guido

> -Daniel
> 
> >
> >  drivers/gpu/drm/etnaviv/etnaviv_drv.c |  1 +
> >  drivers/gpu/drm/etnaviv/etnaviv_drv.h |  1 +
> >  drivers/gpu/drm/etnaviv/etnaviv_gem.c | 32 +++++++++++++++++++++++++++
> >  drivers/gpu/drm/etnaviv/etnaviv_mmu.c |  4 ++++
> >  4 files changed, 38 insertions(+)
> >
> > --
> > 2.28.0
> >
> 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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