From: Daniel Vetter Date: Wed, 27 Aug 2014 08:11:34 +0000 (+0200) Subject: drm/i915: Fix irq enable tracking in driver load X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4868b45de11483d5b307a406d7f1a707699b1702;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git drm/i915: Fix irq enable tracking in driver load A bunch of warnings fire on some ->irq_postinstall hooks since those can enable interrupts (e.g. rps interrupts). And then our ordering self-checks fire and complain. To fix that set the tracking boolen before enabling the irqs with drm_irq_install. Quoting the discussion with Jesse why that's safe: On Tue, Aug 26, 2014 at 11:18 PM, Jesse Barnes wrote: > Yes, it might work, but if you look through the history, we set this > field carefully; first to true in the irq_init code, then to false only > after the irq_install completes. So I think your fragility arguments > apply to this change too. Well we've done it in 4 commits or so, but currently we have: - Set irqs_disabled to true early in driver load to make sure checks that. That's done in irq_init, which is totally not the function that enables interrupts, only the function that initializes all the vtables and similar things. We actually have a fairly sane naming scheme nowadays (not fully consistent ofc): _init is sw setup, _enable/_hw_init is the actual hw setup. That is done in 95f25beddba2ec9510b249740bacc11eca70cf75 - Set irqs_disabled to false right after the irqs are actually enabled. This is done in ed2e6df18935beb3d63613c50103bf9757b2aa85 So my change should only move the flag change over the ->preinstall and ->postinstall hooks. I've done a little audit and didn't spot anything amiss. Furthermore the runtime pm setup already clears irqs_disabled _before_ calling these two hooks. This regression has been introduced in commit ed2e6df18935beb3d63613c50103bf9757b2aa85 Author: Jesse Barnes Date: Fri Jun 20 09:39:36 2014 -0700 drm/i915: clear pm._irqs_disabled field after installing IRQs Cc: Jesse Barnes Cc: Oliver Hartkopp Tested-by: Oliver Hartkopp Signed-off-by: Daniel Vetter Tested-by: Chris Wilson # gm45, ilk Reviewed-by: Jesse Barnes Signed-off-by: Jani Nikula --- diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 2e7f03ad5ee2..9933c26017ed 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -1336,12 +1336,17 @@ static int i915_load_modeset_init(struct drm_device *dev) intel_power_domains_init_hw(dev_priv); + /* + * We enable some interrupt sources in our postinstall hooks, so mark + * interrupts as enabled _before_ actually enabling them to avoid + * special cases in our ordering checks. + */ + dev_priv->pm._irqs_disabled = false; + ret = drm_irq_install(dev, dev->pdev->irq); if (ret) goto cleanup_gem_stolen; - dev_priv->pm._irqs_disabled = false; - /* Important: The output setup functions called by modeset_init need * working irqs for e.g. gmbus and dp aux transfers. */ intel_modeset_init(dev);