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

Pavel Machek
2015-07-01T12:35:24Z

On Wed 2015-07-01 13:53:31, Ville Syrjälä wrote:
> On Wed, Jul 01, 2015 at 11:51:27AM +0200, Pavel Machek wrote:
> > > > > - Embedded panels have a well defined shutdown sequence. We
> > don't
> >
> > > > > have
> > > > > any good reason to not follow this, in fact for some panels the
> > > > > subsequent reinitialization could be problematic in case of a hard
> > > > > power-off. (Thanks to Jani for this info)
> > > >
> > > > Please cite concrete example. I have yet to see machine that would not
> > > > power up on forced power down. In fact, I argue that such machine
> > > > would be very broken, and that such machine does not exist. While we
> > > > have these real machines broken:
> > > >
> > > > > + * Lenovo Thinkpad X301, X61s, X60, T60, X41
> > > > > + * Fujitsu FSC S7110
> > > > > + * Acer Aspire 1830T
> > > >
> > > > What makes you think that BIOS writers will do something different for
> > > > Gen6+ hardware? X301 is not that old.
> > >
> > > Thinkpad X1 Carbon (IVB) is perfectly happy with the D3, so clearly
> > > something changed for Lenovo at least. And most machines (old and new)
> > > have no problems whatsoever with the D3.
> >
> > Well, one machine being happy does not matter that much...
>
> I said most machines, not one.
>
> > as going to
> > D3 has no real benefits.
>
> Sure it does. Eventually we'll want to avoid resuming runtime suspended
> devices when entering system suspend. For broken machines we'd need to
> resume the GPU at that point.

You want to optimize transition between suspend-to-RAM and
hibernation? No? I thought so.

So no benefits, 7 real, broken machines.
Pavel

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