• Dmitry Osipenko's avatar
    drm/tegra: gem: Fix CPU-cache maintenance for BO's allocated using get_pages() · 61b51fb5
    Dmitry Osipenko authored
    The allocated pages need to be invalidated in CPU caches. On ARM32 the
    DMA_BIDIRECTIONAL flag only ensures that data is written-back to DRAM and
    the data stays in CPU cache lines. While the DMA_FROM_DEVICE flag ensures
    that the corresponding CPU cache lines are getting invalidated and nothing
    more, that's exactly what is needed for a newly allocated pages.
    
    This fixes randomly failing rendercheck tests on Tegra30 using the
    Opentegra driver for tests that use small-sized pixmaps (10x10 and less,
    i.e. 1-2 memory pages) because apparently CPU reads out stale data from
    caches and/or that data is getting evicted to DRAM at the time of HW job
    execution.
    
    Fixes: bd43c9f0 ("drm/tegra: gem: Map pages via the DMA API")
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
    Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
    61b51fb5
gem.c 14 KB