diff options
| author | Egbert Eich <eich@suse.de> | 2015-09-23 17:15:27 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2015-09-23 17:56:30 +0300 |
| commit | 0706f17c307b056ff6f1848320ba82d76945a6ff (patch) | |
| tree | 8cbb6ee4a94746516faac04e1eb43363aa088cee /drivers/gpu/drm/i915/intel_crt.c | |
| parent | 8204502a6aa2eab8cd5779020c2881fbc6361a96 (diff) | |
| download | linux-0706f17c307b056ff6f1848320ba82d76945a6ff.tar.xz | |
drm/i915: Avoid race of intel_crt_detect_hotplug() with HPD interrupt, v2
An HPD interrupt may fire while we are in a function that changes
the PORT_HOTPLUG_EN register - especially when an HPD interrupt
storm occurs.
Since the interrupt handler changes the enabled HPD lines when it
detects such a storm the read-modify-write cycles may interfere.
To avoid this, shiled the rmw cycles with IRQ save spinlocks.
Changes since v1:
- Implement a function which takes care of accessing PORT_HOTPLUG_EN.
Signed-off-by: Egbert Eich <eich@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_crt.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_crt.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c index af5e43bef4a4..6ce38e3edf21 100644 --- a/drivers/gpu/drm/i915/intel_crt.c +++ b/drivers/gpu/drm/i915/intel_crt.c @@ -376,7 +376,7 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector) { struct drm_device *dev = connector->dev; struct drm_i915_private *dev_priv = dev->dev_private; - u32 hotplug_en, orig, stat; + u32 stat; bool ret = false; int i, tries = 0; @@ -395,12 +395,12 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector) tries = 2; else tries = 1; - hotplug_en = orig = I915_READ(PORT_HOTPLUG_EN); - hotplug_en |= CRT_HOTPLUG_FORCE_DETECT; for (i = 0; i < tries ; i++) { /* turn on the FORCE_DETECT */ - I915_WRITE(PORT_HOTPLUG_EN, hotplug_en); + i915_hotplug_interrupt_update(dev_priv, + CRT_HOTPLUG_FORCE_DETECT, + CRT_HOTPLUG_FORCE_DETECT); /* wait for FORCE_DETECT to go off */ if (wait_for((I915_READ(PORT_HOTPLUG_EN) & CRT_HOTPLUG_FORCE_DETECT) == 0, @@ -415,8 +415,7 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector) /* clear the interrupt we just generated, if any */ I915_WRITE(PORT_HOTPLUG_STAT, CRT_HOTPLUG_INT_STATUS); - /* and put the bits back */ - I915_WRITE(PORT_HOTPLUG_EN, orig); + i915_hotplug_interrupt_update(dev_priv, CRT_HOTPLUG_FORCE_DETECT, 0); return ret; } |