[Intel-gfx] [PATCH] drm/i915: apply the PCI_D0/D3 hibernation workaround everywhere on pre GEN6

[Mikko Rapeli]

Please, please merge this patch already. Without it hibernation poweroff
is broken for several users. There were some doubts raised over the
approach on lkml review but Imre as maintainer thinks this is the right
thing to do and users like me need this patch.

Tested again with Thinkpad T60 and kernel version 4.1.6.

Tested-by: Mikko Rapeli <mikko.rapeli at iki.fi>

-Mikko

On Tue, Jun 30, 2015 at 05:06:47PM +0300, Imre Deak wrote:
> commit da2bc1b9db3351addd293e5b82757efe1f77ed1d
> Author: Imre Deak <imre.deak at intel.com>
> Date:   Thu Oct 23 19:23:26 2014 +0300
> 
>     drm/i915: add poweroff_late handler
> 
> introduced a regression on old platforms during hibernation. A workaround was
> added in
> 
> commit ab3be73fa7b43f4c3648ce29b5fd649ea54d3adb
> Author: Imre Deak <imre.deak at intel.com>
> Date:   Mon Mar 2 13:04:41 2015 +0200
> 
>     drm/i915: gen4: work around hang during hibernation
> 
> using an explicit blacklist for the GENs/BIOS vendors where the issue was
> reported. Later there we had reports of the same failure on platforms not on
> this list.
> 
> To my best knowledge the correct thing to do is still to put the device to PCI
> D3 state during hibernation, see [1] and [2] for the reasons. This also aligns
> with our future plans to unify more the runtime and system suspend/resume
> paths. Since an exact blacklist seems to be impractical (multiple GENs and
> BIOS vendors are affected) apply the workaround on everything pre GEN6.
> 
> [1] http://lists.freedesktop.org/archives/intel-gfx/2015-February/060710.html
> [2] https://lkml.org/lkml/2015/6/22/274
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=95061
> Reported-by: Ilya Tumaykin <itumaykin at gmail.com>
> Reported-by: Dirk Griesbach <spamthis at freenet.de>
> Reported-by: Pavel Machek <pavel at ucw.cz>
> Reported-by: Mikko Rapeli <mikko.rapeli at iki.fi>
> Reported-by: Paul Bolle <pebolle at tiscali.nl>
> CC: stable at vger.kernel.org
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index e44dc0d..1e675ff 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -664,15 +664,18 @@ static int i915_drm_suspend_late(struct drm_device *drm_dev, bool hibernation)
>  
>  	pci_disable_device(drm_dev->pdev);
>  	/*
> -	 * During hibernation on some GEN4 platforms the BIOS may try to access
> +	 * During hibernation on some 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
> +	 * power down the device properly. The issue was seen on multiple old
> +	 * GENs with different BIOS vendors, so having an explicit blacklist
> +	 * is inpractical; apply the workaround on everything pre GEN6. The
> +	 * platforms where the issue was seen:
> +	 * Lenovo Thinkpad X301, X61s, X60, T60, X41
> +	 * Fujitsu FSC S7110
> +	 * Acer Aspire 1830T
>  	 */
> -	if (!(hibernation &&
> -	      drm_dev->pdev->subsystem_vendor == PCI_VENDOR_ID_LENOVO &&
> -	      INTEL_INFO(dev_priv)->gen == 4))
> +	if (!(hibernation && INTEL_INFO(dev_priv)->gen < 6))
>  		pci_set_power_state(drm_dev->pdev, PCI_D3hot);
>  
>  	return 0;
> -- 
> 2.1.4
>