On Wed, 10 Dec 2014, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > On Thu, Nov 20, 2014 at 04:05:55PM +0200, Imre Deak wrote: >> 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@xxxxxxxxx> >> 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@xxxxxxxxxxxxxxx (v3.15+) >> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> > > Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Pushed to drm-intel-next-fixes, thanks for the patch and review. BR, Jani. > >> --- >> drivers/gpu/drm/i915/i915_irq.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c >> index 8d169e1..4601f53 100644 >> --- a/drivers/gpu/drm/i915/i915_irq.c >> +++ b/drivers/gpu/drm/i915/i915_irq.c >> @@ -3597,7 +3597,7 @@ 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) >> -- >> 1.8.4 >> >> _______________________________________________ >> Intel-gfx mailing list >> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Ville Syrjälä > Intel OTC > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html