Re: [Intel-gfx] [PATCH 2/2] drm/i915: Reinit polling before hpd when resuming

From: David Weinehall
Date: Thu Nov 03 2016 - 14:56:56 EST


On Thu, Nov 03, 2016 at 11:42:38AM -0400, Lyude wrote:
> Now that we don't run the connector reprobing from i915_drm_resume(), we
> need to make it so we don't have to wait for reprobing to finish so that
> we actually speed things up. In order to do this, we need to make sure
> that i915_drm_resume() doesn't get blocked by i915_hpd_poll_init_work()
> while trying to acquire the mode_config lock that
> drm_kms_helper_poll_enable() needs to acquire.
>
> The easiest way to do this is to just enable polling before hpd. This
> shouldn't break anything since at that point we have everything else we
> need for polling enabled.
>
> As well, this should result in a rather significant improvement in how
> quickly we can resume the system.
>
> Signed-off-by: Lyude <lyude@xxxxxxxxxx>
> Cc: David Weinehall <david.weinehall@xxxxxxxxxxxxxxx>

Tested-by: David Weinehall <david.weinehall@xxxxxxxxxxxxxxx>
Reviewed-by: David Weinehall <david.weinehall@xxxxxxxxxxxxxxx>
Testcase: analyze_suspend.py -config config/suspend-callgraph.cfg -filter i915

> ---
> drivers/gpu/drm/i915/i915_drv.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 532cc0f..f605dde 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1595,6 +1595,8 @@ static int i915_drm_resume(struct drm_device *dev)
>
> intel_display_resume(dev);
>
> + drm_kms_helper_poll_enable(dev);
> +
> /*
> * ... but also need to make sure that hotplug processing
> * doesn't cause havoc. Like in the driver load code we don't
> @@ -1614,7 +1616,6 @@ static int i915_drm_resume(struct drm_device *dev)
> intel_opregion_notify_adapter(dev_priv, PCI_D0);
>
> intel_autoenable_gt_powersave(dev_priv);
> - drm_kms_helper_poll_enable(dev);
>
> enable_rpm_wakeref_asserts(dev_priv);
>
> --
> 2.7.4
>
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