From 9184b6831bbe8ffd8843eff66721981bc2cc6eff Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Fri, 23 Oct 2020 09:51:09 -0700 Subject: [PATCH] drm/msm: Do rpm get sooner in the submit path Unfortunately, due to an dev_pm_opp locking interaction with mm->mmap_sem, we need to do pm get before aquiring obj locks, otherwise we can have anger lockdep with the chain: opp_table_lock --> &mm->mmap_sem --> reservation_ww_class_mutex For an explicit fencing userspace, the impact should be minimal as we do all the fence waits before this point. It could result in some needless resumes in error cases, etc. Signed-off-by: Rob Clark Reviewed-by: Kristian H. Kristensen Signed-off-by: Rob Clark --- drivers/gpu/drm/msm/msm_gem_submit.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c index b6c258c8929084..aa3c7af54079a6 100644 --- a/drivers/gpu/drm/msm/msm_gem_submit.c +++ b/drivers/gpu/drm/msm/msm_gem_submit.c @@ -750,11 +750,20 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, ret = submit_lookup_objects(submit, args, file); if (ret) - goto out; + goto out_pre_pm; ret = submit_lookup_cmds(submit, args, file); if (ret) - goto out; + goto out_pre_pm; + + /* + * Thanks to dev_pm_opp opp_table_lock interactions with mm->mmap_sem + * in the resume path, we need to to rpm get before we lock objs. + * Which unfortunately might involve powering up the GPU sooner than + * is necessary. But at least in the explicit fencing case, we will + * have already done all the fence waiting. + */ + pm_runtime_get_sync(&gpu->pdev->dev); /* copy_*_user while holding a ww ticket upsets lockdep */ ww_acquire_init(&submit->ticket, &reservation_ww_class); @@ -831,6 +840,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, out: + pm_runtime_put(&gpu->pdev->dev); +out_pre_pm: submit_cleanup(submit); if (has_ww_ticket) ww_acquire_fini(&submit->ticket);