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| author | Lucas Stach <l.stach@pengutronix.de> | 2016-12-12 16:15:17 +0100 |
|---|---|---|
| committer | Lucas Stach <l.stach@pengutronix.de> | 2017-01-11 10:38:45 +0100 |
| commit | 3546fb0cdac25a79c89d87020566fab52b92867d (patch) | |
| tree | a2e5b1a5ad04f0fd72e9d7ee4d8a3973565eb449 /drivers/gpu/drm/etnaviv | |
| parent | 7ce7d89f48834cefece7804d38fc5d85382edf77 (diff) | |
| download | linux-3546fb0cdac25a79c89d87020566fab52b92867d.tar.gz linux-3546fb0cdac25a79c89d87020566fab52b92867d.tar.xz | |
drm/etnaviv: trick drm_mm into giving out a low IOVA
After rollover of the IOVA space, we want to get a low IOVA address,
otherwise the the games we play by remembering the last IOVA are
pointless. When we search for a free hole with DRM_MM_SEARCH_DEFAULT,
drm_mm will pop the next entry from the free holes stack, which will
likely be a high IOVA. By using DRM_MM_SEARCH_BELOW we can trick
drm_mm into reversing the search and provide us with a low IOVA.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Wladimir van der Laan <laanwj@gmail.com>
Diffstat (limited to 'drivers/gpu/drm/etnaviv')
| -rw-r--r-- | drivers/gpu/drm/etnaviv/etnaviv_mmu.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c index 169ac96e8f08..fe0e85b41310 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c @@ -116,9 +116,14 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu *mmu, struct list_head list; bool found; + /* + * XXX: The DRM_MM_SEARCH_BELOW is really a hack to trick + * drm_mm into giving out a low IOVA after address space + * rollover. This needs a proper fix. + */ ret = drm_mm_insert_node_in_range(&mmu->mm, node, size, 0, mmu->last_iova, ~0UL, - DRM_MM_SEARCH_DEFAULT); + mmu->last_iova ? DRM_MM_SEARCH_DEFAULT : DRM_MM_SEARCH_BELOW); if (ret != -ENOSPC) break; |