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gpu: nvgpu: remove redundant busy()/idle() calls

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gk20a_busy() call in channel_syncpt_incr() and corresponding
gk20a_idle() call in channel_update() are redundant since they
are already encapsulated inside another pair of busy/idle calls

This busy/idle pair will be called only from submit_gpfifo()
and submit_gpfifo() already has its own busy/idle which it
preserves for whole path and hence this redundant pair can be
removed

Also, this prevents a dead lock scenario while do_idle() is in
progress as follows :
- in submit_gpfifo() we call first gk20a_busy() which acquires
  busy read semaphore
- in do_idle() we acquire busy write semaphore and wait for
  current jobs to finish
- now submit_gpfifo() encounters second gk20a_busy() and requests
  busy read semaphore again
- this results in dead lock where do_idle() is waiting for
  submit_gpfifo() to complete and submit_gpfifo() is waiting for
  busy lock held by do_idle() and hence it cannot complete

bug 1529160

Change-Id: I96e4368352f693e93524f0f61689b4447e5331ea
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/434191
(cherry picked from commit c4315c6caa42bab72ba6017c7ded25f4e9363dec)
Reviewed-on: http://git-master/r/435132
Reviewed-by: Sachin Nikam <snikam@nvidia.com>
Tested-by: Sachin Nikam <snikam@nvidia.com>
This commit is contained in:
Deepak Nibade
2014-07-03 18:32:20 +05:30
committed by Dan Willemsen
parent 0b1f9e4272
commit 7c5404fa42
2 changed files with 4 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/gpu/nvgpu/gk20a/channel_gk20a.c
View File

@@ -1414,10 +1414,8 @@ static int gk20a_channel_add_job(struct channel_gk20a *c,
void gk20a_channel_update(struct channel_gk20a *c, int nr_completed)
{
struct gk20a *g = c->g;
struct vm_gk20a *vm = c->vm;
struct channel_gk20a_job *job, *n;
int i;
wake_up(&c->submit_wq);
@@ -1442,7 +1440,7 @@ void gk20a_channel_update(struct channel_gk20a *c, int nr_completed)
list_del_init(&job->list);
kfree(job);
gk20a_idle(g->dev);
gk20a_idle(c->g->dev);
}
/*
@@ -1460,9 +1458,6 @@ void gk20a_channel_update(struct channel_gk20a *c, int nr_completed)
}
mutex_unlock(&c->jobs_lock);
mutex_unlock(&c->submit_lock);
for (i = 0; i < nr_completed; i++)
gk20a_idle(c->g->dev);
}
void add_wait_cmd(u32 *ptr, u32 id, u32 thresh)

13
drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c
View File

@@ -233,16 +233,9 @@ static int __gk20a_channel_syncpt_incr(struct gk20a_channel_sync *s,
thresh = nvhost_syncpt_incr_max_ext(sp->host1x_pdev, sp->id, 1);
if (register_irq) {
/* nvhost action_gpfifo_submit_complete releases this ref. */
err = gk20a_busy(c->g->dev);
if (!err) {
err = nvhost_intr_register_notifier(sp->host1x_pdev,
sp->id, thresh,
gk20a_channel_syncpt_update, c);
if (err)
gk20a_idle(c->g->dev);
}
err = nvhost_intr_register_notifier(sp->host1x_pdev,
sp->id, thresh,
gk20a_channel_syncpt_update, c);
/* Adding interrupt action should never fail. A proper error
* handling here would require us to decrement the syncpt max