Attachment 101893 Details for Bug 80517 – Possible fix

[patch] Possible fix

0001-drm-i915-flush-delayed_resume_work-when-suspending.patch (text/plain), 1.87 KB, created by Paulo Zanoni on 2014-06-27 19:59:10 UTC

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Creator: Paulo Zanoni

Created: 2014-06-27 19:59:10 UTC

Size: 1.87 KB

patch

obsolete

>From 43c562b3fcd44cbb582fb440f13857e267210e9e Mon Sep 17 00:00:00 2001
>From: Paulo Zanoni <paulo.r.zanoni@intel.com>
>Date: Fri, 27 Jun 2014 16:44:43 -0300
>Subject: [PATCH] drm/i915: flush delayed_resume_work when suspending
>
>It is possible that, by the time we run i915_drm_freeze(),
>delayed_resume_work was already queued but did not run yet. If it
>still didn't run after intel_runtime_pm_disable_interrupts(), by the
>time it runs it will try to change the interrupt registers with the
>interrupts already disabled, which will trigger a WARN. We can
>reliably reproduce this with the pm_rpm system-suspend test case.
>
>In order to avoid the problem, we have to flush the work before
>disabling the interrupts. We could also cancel the work instead of
>flushing it, but that would require us to put a runtime PM reference -
>and any other resource we may need in the future - in case the work
>was already queued, so I believe flushing the work is more
>future-proof, although less efficient. But I can also change this part
>if someone requests.
>
>Another thing I tried was to move the intel_suspend_gt_powersave()
>call to before intel_runtime_pm_disable_interrupts(), but since that
>function needs to be called after the interrupts are already disabled,
>due to dev_priv->rps.work, this strategy didn't work.
>
>Testcase: igt/pm_rpm/system-suspend
>Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
>---
> drivers/gpu/drm/i915/i915_drv.c | 2 ++
> 1 file changed, 2 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
>index e64547e..672694b 100644
>--- a/drivers/gpu/drm/i915/i915_drv.c
>+++ b/drivers/gpu/drm/i915/i915_drv.c
>@@ -524,6 +524,8 @@ static int i915_drm_freeze(struct drm_device *dev)
> 			return error;
> 		}
> 
>+		flush_delayed_work(&dev_priv->rps.delayed_resume_work);
>+
> 		intel_runtime_pm_disable_interrupts(dev);
> 		dev_priv->enable_hotplug_processing = false;
> 
>-- 
>2.0.0
>

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Attachments on bug 80517: 101734 | 101893 | 102000

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