Daniel Vetter <daniel@xxxxxxxx> writes: > On Thu, Feb 05, 2015 at 12:16:32PM +0200, Mika Kuoppala wrote: >> We read the coherent current seqno and actual head from ring. >> For hardware access we need to take runtime_pm reference, which brings in >> locking. As this debugfs entry is for debugging hangcheck behaviour, >> including locking problems, we need to be flexible on taking them. >> >> Try to see if we get a lock and if so, get seqno and actual head >> from hardware. If we don't have exclusive access, get lazy coherent >> seqno and print token acthd for which the user can see that the >> seqno is of different nature. >> >> Testcase: igt/pm_rpm/debugfs-read >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88910 >> Tested-by: Ding Heng <hengx.ding@xxxxxxxxx> >> Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> >> --- >> drivers/gpu/drm/i915/i915_debugfs.c | 26 +++++++++++++++++++++++--- >> 1 file changed, 23 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c >> index 9af17fb..5a6b0e2 100644 >> --- a/drivers/gpu/drm/i915/i915_debugfs.c >> +++ b/drivers/gpu/drm/i915/i915_debugfs.c >> @@ -1223,8 +1223,11 @@ out: >> static int i915_hangcheck_info(struct seq_file *m, void *unused) >> { >> struct drm_info_node *node = m->private; >> - struct drm_i915_private *dev_priv = to_i915(node->minor->dev); >> + struct drm_device *dev = node->minor->dev; >> + struct drm_i915_private *dev_priv = dev->dev_private; >> struct intel_engine_cs *ring; >> + u64 acthd[I915_NUM_RINGS]; >> + u32 seqno[I915_NUM_RINGS]; >> int i; >> >> if (!i915.enable_hangcheck) { >> @@ -1232,6 +1235,23 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused) >> return 0; >> } >> >> + if (mutex_trylock(&dev->struct_mutex)) { > > Why do we need dev->struct_mutex here? Apparently intel_runtime_pm_get is fine without it. Cargoculted from the neighbouring debugfs entry. Only thing I can think of is that it reveals if we had exclusive access depending of achtd token value printed. But is that information then of any use I dont know. I'll respin -Mika > -Daniel > >> + intel_runtime_pm_get(dev_priv); >> + >> + for_each_ring(ring, dev_priv, i) { >> + seqno[i] = ring->get_seqno(ring, false); >> + acthd[i] = intel_ring_get_active_head(ring); >> + } >> + >> + intel_runtime_pm_put(dev_priv); >> + mutex_unlock(&dev->struct_mutex); >> + } else { >> + for_each_ring(ring, dev_priv, i) { >> + seqno[i] = ring->get_seqno(ring, true); >> + acthd[i] = -1; >> + } >> + } >> + >> if (delayed_work_pending(&dev_priv->gpu_error.hangcheck_work)) { >> seq_printf(m, "Hangcheck active, fires in %dms\n", >> jiffies_to_msecs(dev_priv->gpu_error.hangcheck_work.timer.expires - >> @@ -1242,12 +1262,12 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused) >> for_each_ring(ring, dev_priv, i) { >> seq_printf(m, "%s:\n", ring->name); >> seq_printf(m, "\tseqno = %x [current %x]\n", >> - ring->hangcheck.seqno, ring->get_seqno(ring, false)); >> + ring->hangcheck.seqno, seqno[i]); >> seq_printf(m, "\taction = %d\n", ring->hangcheck.action); >> seq_printf(m, "\tscore = %d\n", ring->hangcheck.score); >> seq_printf(m, "\tACTHD = 0x%08llx [current 0x%08llx]\n", >> (long long)ring->hangcheck.acthd, >> - (long long)intel_ring_get_active_head(ring)); >> + (long long)acthd[i]); >> seq_printf(m, "\tmax ACTHD = 0x%08llx\n", >> (long long)ring->hangcheck.max_acthd); >> } >> -- >> 1.9.1 >> >> _______________________________________________ >> Intel-gfx mailing list >> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx