Files
linux/drivers/gpu/drm
Daniel Vetter 1bb9e632a0 drm/i915: Only unbind vgacon, not other console drivers
The console subsystem only provides a function to switch to a given
console, but we want to actually only switach away from vgacon.
Unconditionally switching to the dummy console resulted in switching
away from fbcon in multi-gpu setups when other gpu drivers are loaded
before i915.

Then either the reinitialization of fbcon when i915 registers its
fbdev emulation or the teardown of the fbcon driver killed the
machine. So only switch to the dummy console when it's required.

Kudos to Chris for the original idea, I've only refined it a bit to
still unregister vgacon even when it's currently unused.

This regression has been introduced in

commit a4de05268e
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jun 5 16:20:46 2014 +0200

    drm/i915: Kick out vga console

Reported-and-tested-by: Ed Tomlinson <edt@aei.ca>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-07-09 09:52:13 +02:00
..
2014-06-10 09:35:42 +10:00
2014-07-03 07:54:26 +10:00
2014-05-27 15:50:57 +10:00
2014-04-23 10:32:53 +02:00
2014-06-02 02:07:10 +09:00

************************************************************
* For the very latest on DRI development, please see:      *
*     http://dri.freedesktop.org/                          *
************************************************************

The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).

The DRM supports the Direct Rendering Infrastructure (DRI) in four major
ways:

    1. The DRM provides synchronized access to the graphics hardware via
       the use of an optimized two-tiered lock.

    2. The DRM enforces the DRI security policy for access to the graphics
       hardware by only allowing authenticated X11 clients access to
       restricted regions of memory.

    3. The DRM provides a generic DMA engine, complete with multiple
       queues and the ability to detect the need for an OpenGL context
       switch.

    4. The DRM is extensible via the use of small device-specific modules
       that rely extensively on the API exported by the DRM module.


Documentation on the DRI is available from:
    http://dri.freedesktop.org/wiki/Documentation
    http://sourceforge.net/project/showfiles.php?group_id=387
    http://dri.sourceforge.net/doc/

For specific information about kernel-level support, see:

    The Direct Rendering Manager, Kernel Support for the Direct Rendering
    Infrastructure
    http://dri.sourceforge.net/doc/drm_low_level.html

    Hardware Locking for the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/hardware_locking_low_level.html

    A Security Analysis of the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/security_low_level.html