Re: [PATCH 3/7] drm/i915: don't allocate fbcon from stolen memory if it's too big

Chris Wilson
2015-09-23T16:54:28Z

On Wed, Sep 23, 2015 at 12:52:23PM -0300, Paulo Zanoni wrote:
> Technology has evolved and now we have eDP panels with 3200x1800
> resolution. In the meantime, the BIOS guys didn't change the default
> 32mb for stolen memory. On top of that, we can't assume our users will
> be able to increase the default stolen memory size to more than 32mb -
> I'm not even sure all BIOSes allow that.

fbcon is just a small part of the problem, we can trivially fill stolen
with kernel objects even before we let userspace at it. I agree that being
able to prioritise allocation to HW functions is good, but it is not that hard
to write an eviction + migration pass - given that we already have large
chunks of that written. The only issue is that (at least the sketch I
have in mind) will only evict objects so if we have fragmentation
caused by HW functions, allocations can still fail.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre