Re: [PATCH] drm/i915: enable BIOS hang workaround for Lenovo T60 too

[Imre Deak <imre.deak@intel.com>]

On pe, 2015-06-19 at 18:36 +0200, Paul Bolle wrote:
> On Fri, 2015-06-19 at 17:44 +0200, Daniel Vetter wrote:
> > I wonder whether we shouldn't do this unconditionally for gen4 and earlier
> > for Lenovo ... Anyway this needs Cc: stable@vger.kernel.org and is for
> > Jani to pick up.
> > 
> > Thanks for figuring out what's been broken here.
> > -Daniel
> > 
> > >  		pci_set_power_state(drm_dev->pdev, PCI_D3hot);
> > >  
> > >  	return 0;
> 
> Just two days ago we discussed this bug too, see
> https://lkml.org/lkml/2015/6/17/327 . That message contains a link to a
> patch I cobbled together for yet another ThinkPad hitting this, but with
> PCI_SUBVENDOR_ID_IBM involved.

To summarize, since we extended the range of platforms to apply the
workaround in
commit ab3be73fa7b43f4c3648ce29b5fd649ea54d3adb
Author: Imre Deak <imre.deak@intel.com>
Date:   Mon Mar 2 13:04:41 2015 +0200

    drm/i915: gen4: work around hang during hibernation

we had the following reports I know of with the same issue:
- Acer Aspire 1830T by Ilya (Gen5) [1]
- Fujitsu FSC S7110 by Dirk (Gen4.5) [2]
- ThinkPad X60 by Pavel (Gen4.5) [3]
- ThinkPad T60 by Mikko (Gen4.5) [4]
- ThinkPad X41 by Paul (Gen3) [5]

Based on this I would give up on a vendor specific blacklist and apply
the workaround for anything < GEN6.

About completely reverting the original
commit da2bc1b9db3351addd293e5b82757efe1f77ed1d
Author: Imre Deak <imre.deak@intel.com>
Date:   Thu Oct 23 19:23:26 2014 +0300

    drm/i915: add poweroff_late handler

I still believe that the normal thing to do is to power off the device
during S4. This is the default action taken by the kernel's PCI core for
every device. S4 is not a state where it'd be guaranteed that all
devices are powered off, there may be wake-up devices that are still
powered for example, so powering off any devices explicitly that are not
wake-up sources makes sense to me. I think we need a point where we stop
applying this workaround and GEN6 seems like a good point for that,
since I haven't seen any report past GEN5.

--Imre

[1] https://bugzilla.kernel.org/show_bug.cgi?id=94241#c8
[2] https://bugzilla.kernel.org/show_bug.cgi?id=95061
[3] https://lkml.org/lkml/2015/6/17/404
[4] http://lists.freedesktop.org/archives/intel-gfx/2015-June/069305.html
[5] https://lkml.org/lkml/2015/3/18/133


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