Messages in this thread | | | Date | Thu, 26 Sep 2013 18:16:47 +0200 | From | Mario Kleiner <> | Subject | Re: [Intel-gfx] BUG: sleeping function called from invalid context on 3.10.10-rt7 |
| |
On 25.09.13 16:13, Steven Rostedt wrote: > On Wed, 25 Sep 2013 06:32:10 +0200 > Mario Kleiner <mario.kleiner@tuebingen.mpg.de> wrote: > > >> But given the new situation, your proposal is great! If we push the >> clock readouts into the get_scanoutpos routine, we can make this robust >> without causing grief for the rt people and without the need for a new >> separate lock for display regs in intel-kms. >> >> E.g., for intel-kms: >> >> i915_get_crtc_scanoutpos(..., ktime_t *stime, ktime_t *etime) >> { >> ... >> spin_lock_irqsave(...uncore.lock); >> preempt_disable(); >> *stime = ktime_get(); >> position = __raw_i915_read32(dev_priv, PIPEDSL(pipe)); >> *etime = ktime_get(); >> preempt_enable(); >> spin_unlock_irqrestore(...uncore.lock) >> ... >> } >> >> With your patchset to reduce the amount of register reads needed in that >> function, and given that forcewake handling isn't needed for these >> registers, this should make it robust again and wouldn't need new locks. >> >> Unless ktime_get is also a bad thing to do in a preempt disabled section? > > ktime_get() works fine in preempt_disable sections, although it may add > some latencies, but you shouldn't need to worry about it. > > I like this solution the best too, but if it does go in, I would ask to > send us the patch for adding the preempt_disable() and we can add the > preempt_disable_rt() to it. Why make mainline have a little more > overhead? > > -- Steve
Good! I will do that. Thanks for clarifying the irq and constraints on raw locks in the other thread.
-mario
> _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx >
| |