Re: [PATCH 4/5] drm/i915: Wrap the preallocated BIOS framebuffer and preserve for KMS fbcon v7

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Tue, 26 Nov 2013 14:09:48 +0000
Chris Wilson <chris@chris-wilson.co.uk> wrote:

> On Mon, Nov 25, 2013 at 03:51:18PM -0800, Jesse Barnes wrote:
> > Retrieve current framebuffer config info from the regs and create an fb
> > object for the buffer the BIOS or boot loader left us.  This should
> > allow for smooth transitions to userspace apps once we finish the
> > initial configuration construction.
> > 
> > v2: check for non-native modes and adjust (Jesse)
> >     fixup aperture and cmap frees (Imre)
> >     use unlocked unref if init_bios fails (Jesse)
> >     fix curly brace around DSPADDR check (Imre)
> >     comment failure path for pin_and_fence (Imre)
> > v3: fixup fixup of aperture frees (Chris)
> > v4: update to current bits (locking & pin_and_fence hack) (Jesse)
> > v5: move fb config fetch to display code (Jesse)
> >     re-order hw state readout on initial load to suit fb inherit (Jesse)
> >     re-add pin_and_fence in fbdev code to make sure we refcount properly (Je
> > v6: rename to plane_config (Daniel)
> >     check for valid object when initializing BIOS fb (Jesse)
> >     split from plane_config readout and other display changes (Jesse)
> >     drop use_bios_fb option (Chris)
> >     update comments (Jesse)
> >     rework fbdev_init_bios for clarity (Jesse)
> >     drop fb obj ref under lock (Chris)
> > v7: use fb object from plane_config instead (Ville)
> > 
> > Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> 
> Hmm, quietly steals plane_config->fb you mean. Other than bikeshedding
> the kzalloc(intel_fbdev) and the clarity of
> intel_fb_init/intel_fb_init_bios, I don't see anything else. The fb
> lifetime of plane_config->fb is extremely ugly though (the theft could
> be made a little more obvious for instance) and still leaked upon failure?

I free it on failure in fb_init_bios, but maybe I missed an error path?

I agree on the lifetime handling, but it was either this or an ugly
copy of the fb object in the bios function.  And even then we'd have to
find a place to free it that made sense (there is no such place today).

I did comment the field in the struct at least...

-- 
Jesse Barnes, Intel Open Source Technology Center