From d9853490176c88fff71d03ec9a174b77011f5026 Mon Sep 17 00:00:00 2001 From: Lucas Stach Date: Thu, 28 Jul 2016 11:50:48 +0200 Subject: drm/etnaviv: take GPU lock later in the submit process Both the fence and event alloc are safe to be done without holding the GPU lock, as they either don't need any locking (fences) or are protected by their own lock (events). This solves a bad locking interaction between the submit path and the recover worker. If userspace manages to exhaust all available events while the GPU is hung, the submit will wait for events to become available holding the GPU lock. The recover worker waits for this lock to become available before trying to recover the GPU which frees up the allocated events. Essentially both paths are deadlocked until the submit path times out waiting for available events, failing the submit that could otherwise be handled just fine if the recover worker had the chance to bring the GPU back in a working state. Signed-off-by: Lucas Stach Reviewed-by: Christian Gmeiner diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c index 87ef341..b382cf5 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c @@ -1333,8 +1333,6 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu, if (ret < 0) return ret; - mutex_lock(&gpu->lock); - /* * TODO * @@ -1348,16 +1346,18 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu, if (unlikely(event == ~0U)) { DRM_ERROR("no free event\n"); ret = -EBUSY; - goto out_unlock; + goto out_pm_put; } fence = etnaviv_gpu_fence_alloc(gpu); if (!fence) { event_free(gpu, event); ret = -ENOMEM; - goto out_unlock; + goto out_pm_put; } + mutex_lock(&gpu->lock); + gpu->event[event].fence = fence; submit->fence = fence->seqno; gpu->active_fence = submit->fence; @@ -1395,9 +1395,9 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu, hangcheck_timer_reset(gpu); ret = 0; -out_unlock: mutex_unlock(&gpu->lock); +out_pm_put: etnaviv_gpu_pm_put(gpu); return ret; -- cgit v0.10.2