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| author | Imre Deak <imre.deak@intel.com> | 2014-11-20 16:05:55 +0200 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2014-12-11 16:06:10 +0200 |
| commit | c352d1ba1e1e2c8a96af660944a58e86b12ac4af (patch) | |
| tree | 87f84c9eafa367334a9d52068d870ccc56fba93c | |
| parent | 9f49c37635d5c2a801f7670d5fbf0b25ec461f2c (diff) | |
| download | linux-c352d1ba1e1e2c8a96af660944a58e86b12ac4af.tar.gz linux-c352d1ba1e1e2c8a96af660944a58e86b12ac4af.tar.xz | |
drm/i915: vlv: fix IRQ masking when uninstalling interrupts
irq_mask should include all IRQ bits that we want to mask, but atm we
set it incorrectly to the inverse of this. If the mask is used
subsequently to enable/disable some IRQ bits, we may unintentionally
unmask unrelated IRQs. I can't see any way that this can lead to a real
problem in the current -nightly code, since the first place the mask
will be used next (after a suspend/resume cycle) is in
valleyview_irq_postinstall(), but the mask is reset there to its proper
value.
This causes a problem in the upstream kernel though, where - due to another
issue - the mask is used in the above way to disable only the display IRQs.
This other issue is fixed by:
commit 950eabaf5a87257040e0c207be09487954113f54
Author: Imre Deak <imre.deak@intel.com>
Date: Mon Sep 8 15:21:09 2014 +0300
drm/i915: vlv: fix display IRQ enable/disable
Interestingly, even with the above two bugs, we shouldn't in theory have
any real problems (arguably a famous last sentence:). That's because
even if we unmask something unintentionally via the VLV_IMR/VLV_IER
register the master IRQ masking bit in VLV_MASTER_IER is still set and
should prevent all i915 interrupts. According to my testing on an ASUS
T100 with DSI output this isn't the case at least with the
MIPIA_INTERRUPT. Leaving this one unmasked in IMR/IER, while having
VLV_MASTER_IER set to 0 may lead to a lockup during system suspend as
shown in the bugzilla ticket below. This fix should get rid of the
problem reported there in upstream and older kernels.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85920
Cc: stable@vger.kernel.org (v3.15+)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
| -rw-r--r-- | drivers/gpu/drm/i915/i915_irq.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 981834b0f9b6..8bab2ab228b8 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -3609,7 +3609,7 @@ static void vlv_display_irq_uninstall(struct drm_i915_private *dev_priv) vlv_display_irq_reset(dev_priv); - dev_priv->irq_mask = 0; + dev_priv->irq_mask = ~0; } static void valleyview_irq_uninstall(struct drm_device *dev) |