linux-kernel - Re: [Intel-gfx] [PATCH 5/5] drm/i915: Kick out vga console

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Date:	Mon, 07 Jul 2014 06:59:47 -0400
From:	Ed Tomlinson <edt@....ca>
To:	Chris Wilson <chris@...is-wilson.co.uk>,
	Intel Graphics Development <intel-gfx@...ts.freedesktop.org>,
	DRI Development <dri-devel@...ts.freedesktop.org>,
	LKML <linux-kernel@...r.kernel.org>,
	David Herrmann <dh.herrmann@...il.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	linux-fbdev@...r.kernel.org,
	Jani Nikula <jani.nikula@...ux.intel.com>,
	Dave Airlie <airlied@...ux.ie>
Subject: Re: [Intel-gfx] [PATCH 5/5] drm/i915: Kick out vga console

Daniel,

Just to be sure.  The intel card here should not be claiming the real console.  It does
not have an output device and the bios set set so the radeon is the primary device.

Ed


On Monday 07 July 2014 10:48:26 Daniel Vetter wrote:
> On Mon, Jun 30, 2014 at 07:59:55AM +0100, Chris Wilson wrote:
> > On Sat, Jun 28, 2014 at 11:55:19PM -0400, Ed Tomlinson wrote:
> > > On Saturday 28 June 2014 15:28:22 Ed Tomlinson wrote:
> > > 
> > > Resend without html krud which causes list to bounce the message.
> > > 
> > > > Hi
> > > > 
> > > > This commit ( a4de05268e674e8ed31df6348269e22d6c6a1803 ) hangs my boot with 3.16-git.  Reverting it lets the boot proceed. 
> > > > 
> > > > I have an i7 with a built-in i915 and an pcie r7 260x.  The R7 is the primary console.  The i915 is initialized
> > > > but does not have a physical display attached.
> > > > 
> > > > With the patch applied the boot stops at the messages:
> > > > 
> > > > [drm] Memory usable by graphics device = 2048M
> > > > [drm] Replacing VGA console driver
> > 
> > The issue looks like that we are ripping out the radeon fb_con whilst it
> > is active and that upsets everyone. In which case, I think the
> > compromise is:
> > 
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> > index 5f44581..4915f1d 100644
> > --- a/drivers/gpu/drm/i915/i915_dma.c
> > +++ b/drivers/gpu/drm/i915/i915_dma.c
> > @@ -1439,18 +1439,20 @@ static int i915_kick_out_vgacon(struct drm_i915_private *dev_priv)
> >  #else
> >  static int i915_kick_out_vgacon(struct drm_i915_private *dev_priv)
> >  {
> > -       int ret;
> > +       int ret = 0;
> >  
> >         DRM_INFO("Replacing VGA console driver\n");
> >  
> >         console_lock();
> > -       ret = do_take_over_console(&dummy_con, 0, MAX_NR_CONSOLES - 1, 1);
> > -       if (ret == 0) {
> > -               ret = do_unregister_con_driver(&vga_con);
> > -
> > -               /* Ignore "already unregistered". */
> > -               if (ret == -ENODEV)
> > -                       ret = 0;
> > +       if (con_is_bound(&vga_con)) {
> > +               ret = do_take_over_console(&dummy_con, 0, MAX_NR_CONSOLES - 1, 1);
> > +               if (ret == 0) {
> > +                       ret = do_unregister_con_driver(&vga_con);
> 
> Hm, we should only conditionalize the take_over_console - unregistering
> vga_con is kinda the point to make sure it's gone for real. Ed, can you
> please retest with the if (con_is_bound) check just for the
> do_take_over_console call?
> 
> Still puzzled wtf is going on here since as David says this should be a
> no-op.
> 
> Thanks, Daniel
> > +
> > +                       /* Ignore "already unregistered". */
> > +                       if (ret == -ENODEV)
> > +                               ret = 0;
> > +               }
> >         }
> >         console_unlock();
> > 
> > -Chris
> > 
> 
> 

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