[Intel-gfx] [PATCH] drm/i915: add Intel specific initial config function

Jesse Barnes jbarnes at virtuousgeek.org
Fri Apr 3 02:01:08 CEST 2009

On Thu, 2 Apr 2009 15:21:50 -0700
Jesse Barnes <jbarnes at virtuousgeek.org> wrote:

> Pushing the initial configuration down into the driver makes it easier
> to add platform specific default configuration algorithms, and and
> speed up the boot process.
> This patch adds an i915 specific initial config function which
> defaults to using LVDS as the primary head, if present.  It also adds
> a new i915 module parameter, "primary", which can be used to specify
> an alternate primary head to be used for the fb console, and panic
> and lastclose configuration.  It takes a simple string indicating the
> preferred connector, e.g.  "VGA-1" or "DVI-1".
> This version includes the fix for the connector status failure bug
> triggered by this change.  At drm_mode_getconnector time we really do
> want to know the current status, so call it there instead of relying
> on the previously set value from initial probing.

As discussed on IRC this new interface is pretty limited, and the
primary default can cause trouble on machines where LVDS detection is
broken (iow many media boxes).  However I do think we'll need chip
specific initial config generation at some point.

But we also need a way to specify a config on the command line at boot
time, both to work around bugs and to allow for site/platform specific
configuration without the need for source changes.

So what info do we need?
  - fbcon outputs - where kernel output and panic messages will appear
  - output modes (including modeline, refresh, bpp is up to fbcon?)

Beyond that I think it's all userspace; the initrd or rootfs will start
something and it will either use the currently set modes or set up its
own, so I'm not sure we need a big initial config mechanism.

Jesse Barnes, Intel Open Source Technology Center

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