Re: [PATCH] DRM / i915: Fix resume regression on MSI Wind U100 w/oKMS

From: Linus Torvalds
Date: Fri Jan 08 2010 - 19:02:55 EST

On Sat, 9 Jan 2010, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
> Commit cbda12d77ea590082edb6d30bd342a67ebc459e0 (drm/i915: implement
> new pm ops for i915), among other things, removed the .suspend and
> .resume pointers from the struct drm_driver object in i915_drv.c,
> which broke resume without KMS on my MSI Wind U100.
> Fix this by reverting that part of commit cbda12d77ea59.

Hmm. I get the feeling that perhaps the of the drm_driver callbacks was
very muchintentional, and that the code presumably wants to be called
purely through the PCI layer, and not through the "drm class" logic at

Your patch seems like it would always execute the silly class suspend even
though we explicitly don't want to. And a much nicer fix would seem to
register the thing properly as a PCI driver even if you don't then use

So it looks to me like the problem is that drm_init() will register the
driver as a real PCI driver only if

driver->driver_features & DRIVER_MODESET

and otherwise it does that very odd "stealth mode manual scanning" thing
which doesn't register it as a proper PCI driver.

So could we instead make that "disable KSM" _just_ disable the mode
setting part, not disable the "I'm a real driver" part?

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