linux-kernel - Re: [PATCH RESEND 2/2] drm/i915: prevent the vgacon from ever reloading

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Date:	Fri, 27 Nov 2015 15:40:32 +0000
From:	Emil Velikov <emil.l.velikov@...il.com>
To:	Daniel Vetter <daniel.vetter@...ll.ch>
Cc:	Intel Graphics Development <intel-gfx@...ts.freedesktop.org>,
	LKML <linux-kernel@...r.kernel.org>,
	DRI Development <dri-devel@...ts.freedesktop.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH RESEND 2/2] drm/i915: prevent the vgacon from ever reloading

On 27 November 2015 at 15:10, Daniel Vetter <daniel.vetter@...ll.ch> wrote:
> It only leads to bloodshed and tears - we don't bother to restore a
> working legacy vga hw setup.
>
> On haswell with the new dynamic power well code this leads to even
> more hilarity since for some configurations the hardware is simply no
> longer there.
>
> The actual implementation is a bit a hack - we realy on fbcon to kick
> out the vgacon. To make this also work with I915_FBDEV=n (or FBCON=n)
> and VGA_CONSOLE=y i915 already unregisters the vga console manually
> early in the driver load sequence.
>
Interesting... nv50 and later GPUs are in a roughly similar shame
afaict. They lack the dedicated hardware and no one really bothered
figuring out how to restore things to a working shape [1].

Then again, upon sequential load of the nouveau module the GPU gets
initialised properly, where you can get X (weston?) up and running
without issues. Am I thinking about a different thing ?

I take it that you guys do less of the (re)initialisation dance, to
ensure faster boot times ?

Thanks,
Emil

[1] http://nouveau.freedesktop.org/wiki/KernelModeSetting/#deactivatingkmsandunloadingnouveau
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