drm/etnaviv: keep MMU context across runtime suspend/resume

BugLink: https://bugs.launchpad.net/bugs/1946802
commit 8f3eea9d01d7b0f95b0fe04187c0059019ada85b upstream.

The MMU state may be kept across a runtime suspend/resume cycle, as we
avoid a full hardware reset to keep the latency of the runtime PM small.

Don't pretend that the MMU state is lost in driver state. The MMU
context is pushed out when new HW jobs with a different context are
coming in. The only exception to this is when the GPU is unbound, in
which case we need to make sure to also free the last active context.

Cc: stable@vger.kernel.org # 5.4
Reported-by: Michael Walle <michael@walle.cc>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Michael Walle <michael@walle.cc>
Tested-by: Marek Vasut <marex@denx.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 60410c2fd2be2318b7dd00e84ed7ce4299e3fdf7..efec0bbf85230b13de74d2b4b29fcb1ce5341f57 100644 (file)
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1547,9 +1547,6 @@ static int etnaviv_gpu_hw_suspend(struct etnaviv_gpu *gpu)
                 */
                etnaviv_gpu_wait_idle(gpu, 100);
 
-               etnaviv_iommu_context_put(gpu->mmu_context);
-               gpu->mmu_context = NULL;
-
                gpu->fe_running = false;
        }
 
@@ -1698,6 +1695,9 @@ static void etnaviv_gpu_unbind(struct device *dev, struct device *master,
        etnaviv_gpu_hw_suspend(gpu);
 #endif
 
+       if (gpu->mmu_context)
+               etnaviv_iommu_context_put(gpu->mmu_context);
+
        if (gpu->initialized) {
                etnaviv_cmdbuf_free(&gpu->buffer);
                etnaviv_iommu_global_fini(gpu);