On Wed, 21 Oct 2015, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > On Wed, Oct 21, 2015 at 05:22:43PM +0300, Jani Nikula wrote: >> commit 0706f17c307b056ff6f1848320ba82d76945a6ff >> Author: Egbert Eich <eich@xxxxxxx> >> Date: Wed Sep 23 16:15:27 2015 +0200 >> >> drm/i915: Avoid race of intel_crt_detect_hotplug() with HPD interrupt, v2 >> >> added a check with WARN to ensure only bits within the mask are >> enabled. Turns out that doesn't hold for G4X, which spits out: >> >> [ 2.641439] ------------[ cut here ]------------ >> [ 2.641444] WARNING: CPU: 0 PID: 1 at drivers/gpu/drm/i915/i915_irq.c:182 i915_hotplug_interrupt_update_locked+0x45/0x83() >> [ 2.641446] WARN_ON(bits & ~mask) >> etc. >> >> Add CRT_HOTPLUG_ACTIVATION_PERIOD_64 to the mask to fix the warning. >> >> Reported-by: Oleksij Rempel <linux@xxxxxxxxxxxxxxxx> >> References: https://bugzilla.kernel.org/show_bug.cgi?id=104991 >> Fixes: 0706f17c307b ("drm/i915: Avoid race of intel_crt_detect_hotplug() with HPD interrupt, v2") >> Cc: Egbert Eich <eich@xxxxxxx> >> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> >> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> >> --- >> drivers/gpu/drm/i915/i915_irq.c | 7 ++++--- >> 1 file changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c >> index 7f91f74961f4..5b9f63d4318b 100644 >> --- a/drivers/gpu/drm/i915/i915_irq.c >> +++ b/drivers/gpu/drm/i915/i915_irq.c >> @@ -4236,9 +4236,10 @@ static void i915_hpd_irq_setup(struct drm_device *dev) >> >> /* Ignore TV since it's buggy */ >> i915_hotplug_interrupt_update_locked(dev_priv, >> - (HOTPLUG_INT_EN_MASK >> - | CRT_HOTPLUG_VOLTAGE_COMPARE_MASK), >> - hotplug_en); >> + HOTPLUG_INT_EN_MASK | >> + CRT_HOTPLUG_VOLTAGE_COMPARE_MASK | >> + CRT_HOTPLUG_ACTIVATION_PERIOD_64, >> + hotplug_en); > > Or maybe just ~CRT_HOTPLUG_FORCE_DETECT ? This patch already potentially changes behaviour by explicitly setting the activation period to zero (CRT_HOTPLUG_ACTIVATION_PERIOD_32) on non-g4x. Previously it was "don't care". Call me coward, but I am not comfortable with setting the rest of the bits to zero, at least not in the context of this fix, and risking regressions on old machines. BR, Jani. > >> } >> >> static irqreturn_t i965_irq_handler(int irq, void *arg) >> -- >> 2.1.4 >> >> _______________________________________________ >> Intel-gfx mailing list >> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Ville Syrjälä > Intel OTC -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
