[Intel-gfx] [PATCH] i915: remove pm_qos request on error

[Stanislaw Gruszka]

Not removing pm qos request and free memory for it can cause crash,
when some other driver use pm qos. For example, this oops:

BUG: unable to handle kernel paging request at fffffffffffffff8
IP: [<ffffffff81307a6b>] plist_add+0x5b/0xd0
Call Trace:
 [<ffffffff810acf25>] pm_qos_update_target+0x125/0x1e0
 [<ffffffff810ad071>] pm_qos_add_request+0x91/0x100
 [<ffffffffa053ec14>] e1000_open+0xe4/0x5b0 [e1000e]

was caused by earlier i915 probe failure:

[drm:i915_report_and_clear_eir] *ERROR* EIR stuck: 0x00000010, masking
[drm:init_ring_common] *ERROR* render ring initialization failed ctl 0001f001 head 00003004 tail 00000000 start 00003000
[drm:i915_driver_load] *ERROR* failed to init modeset
i915: probe of 0000:00:02.0 failed with error -5

Bug report:
http://bugzilla.redhat.com/show_bug.cgi?id=1057533

Reported-by: Giandomenico De Tullio <ghisha at gmail.com>
Cc: stable at vger.kernel.org
Signed-off-by: Stanislaw Gruszka <sgruszka at redhat.com>
---
 drivers/gpu/drm/i915/i915_dma.c | 4 ++++
 drivers/gpu/drm/i915/i915_irq.c | 2 --
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 5c64842..e141a32 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1603,6 +1603,9 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		goto out_mtrrfree;
 	}
 
+	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY,
+			   PM_QOS_DEFAULT_VALUE);
+
 	intel_irq_init(dev);
 	intel_uncore_sanitize(dev);
 
@@ -1679,6 +1682,7 @@ out_gem_unload:
 
 	intel_teardown_gmbus(dev);
 	intel_teardown_mchbar(dev);
+	pm_qos_remove_request(&dev_priv->pm_qos);
 	destroy_workqueue(dev_priv->wq);
 out_mtrrfree:
 	arch_phys_wc_del(dev_priv->gtt.mtrr);
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 5d1dedc..09e268a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3784,8 +3784,6 @@ void intel_irq_init(struct drm_device *dev)
 	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
 		    (unsigned long) dev_priv);
 
-	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
-
 	if (IS_GEN2(dev)) {
 		dev->max_vblank_count = 0;
 		dev->driver->get_vblank_counter = i8xx_get_vblank_counter;
-- 
1.7.11.7