Re: [PATCH v2] drm/i915: gen4: work around hang during hibernation

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 02 Mar 2015, Imre Deak <imre.deak@intel.com> wrote:
> Bjørn reported that his machine hang during hibernation and eventually
> bisected the problem to the following commit:
>
> commit da2bc1b9db3351addd293e5b82757efe1f77ed1d
> Author: Imre Deak <imre.deak@intel.com>
> Date:   Thu Oct 23 19:23:26 2014 +0300
>
>     drm/i915: add poweroff_late handler
>
> The problem seems to be that after the kernel puts the device into D3
> the BIOS still tries to access it, or otherwise assumes that it's in D0.
> This is clearly bogus, since ACPI mandates that devices are put into D3
> by the OSPM if they are not wake-up sources. In the future we want to
> unify more of the driver's runtime and system suspend paths, for example
> by skipping all the system suspend/hibernation hooks if the device is
> runtime suspended already. Accordingly for all other platforms the goal
> is still to properly power down the device during hibernation.
>
> v2:
> - Another GEN4 Lenovo laptop had the same issue, while platforms from
>   other vendors (including mobile and desktop, GEN4 and non-GEN4) seem
>   to work fine. Based on this apply the workaround on all GEN4 Lenovo
>   platforms.
> - add code comment about failing platforms (Ville)
>
> Reference: http://lists.freedesktop.org/archives/intel-gfx/2015-February/060633.html
> Reported-and-bisected-by: Bjørn Mork <bjorn@mork.no>
> Signed-off-by: Imre Deak <imre.deak@intel.com>

Bjørn, I would really appreciate your Tested-by on this patch before I
queue it for v4.0 and cc: stable for v3.19.

BR,
Jani.


> ---
>  drivers/gpu/drm/i915/i915_drv.c | 30 +++++++++++++++++++++++++-----
>  1 file changed, 25 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 4badb23..ff3662f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -637,7 +637,7 @@ static int i915_drm_suspend(struct drm_device *dev)
>  	return 0;
>  }
>  
> -static int i915_drm_suspend_late(struct drm_device *drm_dev)
> +static int i915_drm_suspend_late(struct drm_device *drm_dev, bool hibernation)
>  {
>  	struct drm_i915_private *dev_priv = drm_dev->dev_private;
>  	int ret;
> @@ -651,7 +651,17 @@ static int i915_drm_suspend_late(struct drm_device *drm_dev)
>  	}
>  
>  	pci_disable_device(drm_dev->pdev);
> -	pci_set_power_state(drm_dev->pdev, PCI_D3hot);
> +	/*
> +	 * During hibernation on some GEN4 platforms the BIOS may try to access
> +	 * the device even though it's already in D3 and hang the machine. So
> +	 * leave the device in D0 on those platforms and hope the BIOS will
> +	 * power down the device properly. Platforms where this was seen:
> +	 * Lenovo Thinkpad X301, X61s
> +	 */
> +	if (!(hibernation &&
> +	      drm_dev->pdev->subsystem_vendor == PCI_VENDOR_ID_LENOVO &&
> +	      INTEL_INFO(dev_priv)->gen == 4))
> +		pci_set_power_state(drm_dev->pdev, PCI_D3hot);
>  
>  	return 0;
>  }
> @@ -677,7 +687,7 @@ int i915_suspend_legacy(struct drm_device *dev, pm_message_t state)
>  	if (error)
>  		return error;
>  
> -	return i915_drm_suspend_late(dev);
> +	return i915_drm_suspend_late(dev, false);
>  }
>  
>  static int i915_drm_resume(struct drm_device *dev)
> @@ -965,7 +975,17 @@ static int i915_pm_suspend_late(struct device *dev)
>  	if (drm_dev->switch_power_state == DRM_SWITCH_POWER_OFF)
>  		return 0;
>  
> -	return i915_drm_suspend_late(drm_dev);
> +	return i915_drm_suspend_late(drm_dev, false);
> +}
> +
> +static int i915_pm_poweroff_late(struct device *dev)
> +{
> +	struct drm_device *drm_dev = dev_to_i915(dev)->dev;
> +
> +	if (drm_dev->switch_power_state == DRM_SWITCH_POWER_OFF)
> +		return 0;
> +
> +	return i915_drm_suspend_late(drm_dev, true);
>  }
>  
>  static int i915_pm_resume_early(struct device *dev)
> @@ -1535,7 +1555,7 @@ static const struct dev_pm_ops i915_pm_ops = {
>  	.thaw_early = i915_pm_resume_early,
>  	.thaw = i915_pm_resume,
>  	.poweroff = i915_pm_suspend,
> -	.poweroff_late = i915_pm_suspend_late,
> +	.poweroff_late = i915_pm_poweroff_late,
>  	.restore_early = i915_pm_resume_early,
>  	.restore = i915_pm_resume,
>  
> -- 
> 2.1.0
>

-- 
Jani Nikula, Intel Open Source Technology Center
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