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

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>

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 24d514e70f9859cfddb948c653111058024481f2..0757dcbe6913a719f82c5c46a02edfbdaee13fbd 100644 (file)
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1596,9 +1596,6 @@ 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;
        }
 
@@ -1747,6 +1744,9 @@ 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);