From 802c7eb646848d769a07704c16f7a3bbec9e5829 Mon Sep 17 00:00:00 2001 From: Jesse Barnes Date: Tue, 5 May 2009 16:03:48 -0700 Subject: [PATCH] drm/i915: sanity check IER at wait_request time We might sleep here anyway so I hope an extra uncached read is ok to add. In #20896 we found that vbetool clobbers the IER. In KMS mode this is particularly bad since we don't set the interrupt regs late (in EnterVT), so we'd fail to get *any* interrupts at all after X started (since some distros have scripts that call vbetool at X startup apparently). So this patch checks IER at wait_request time, and re-enables interrupts if it's been clobbered. In a proper config this check should never be triggered. This is really a distro issue, but having a sanity check is nice, as long as it doesn't have a real performance hit. Tested-by: Mateusz Kaduk Signed-off-by: Jesse Barnes [anholt: Moved the check inside of the sleeping case to avoid perf cost] Signed-off-by: Eric Anholt --- drivers/gpu/drm/i915/i915_gem.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index ee896d91c5bc..b189b49c7602 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1691,11 +1691,20 @@ static int i915_wait_request(struct drm_device *dev, uint32_t seqno) { drm_i915_private_t *dev_priv = dev->dev_private; + u32 ier; int ret = 0; BUG_ON(seqno == 0); if (!i915_seqno_passed(i915_get_gem_seqno(dev), seqno)) { + ier = I915_READ(IER); + if (!ier) { + DRM_ERROR("something (likely vbetool) disabled " + "interrupts, re-enabling\n"); + i915_driver_irq_preinstall(dev); + i915_driver_irq_postinstall(dev); + } + dev_priv->mm.waiting_gem_seqno = seqno; i915_user_irq_get(dev); ret = wait_event_interruptible(dev_priv->irq_queue,