drm: Update the device-independent code to match Linux 3.8.13

This update brings few features:
o Support for the setmaster/dropmaster ioctls. For instance, they
are used to run multiple X servers simultaneously.
o Support for minor devices. The only user-visible change is a new
entry in /dev/dri but it is useless at the moment. This is a
first step to support render nodes [1].

The main benefit is to greatly reduce the diff with Linux (at the
expense of an unreadable commit diff). Hopefully, next upgrades will be
easier.

No updates were made to the drivers, beside adapting them to API
changes.

[1] https://en.wikipedia.org/wiki/Direct_Rendering_Manager#Render_nodes

r280814 is merged at the same time to avoid a short window where RANDR
might be broken:

drm: Import Linux commit 9bc3cd5673d84d29272fa7181a4dfca83cbb48c1

Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date: Fri May 31 12:17:08 2013 +0000

drm: Sort connector modes based on vrefresh

Keeping the modes sorted by vrefresh before the pixel clock makes the
mode list somehow more pleasing to the eye.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

PR: 198936 (r280814)
Tested by: Many people
MFC of: r280183, r280187 (original commit by glebius), r280814
Relnotes: yes

MFC r277487:
An update for the i915 GPU driver, which brings the code up to Linux
commit 4d93914ae3db4a897ead4b.

MFC r277959 (by adrian):
Fix backlight for ivybridge based laptops (and whatever else comes through
this codepath.)

MFC r278146:
Do not attach to the unsupported chipsets, unless magic tunable is
frobbed.

MFC r278147, r278148:
Fix sign for the error code returned from the driver-specific code.

MFC r278152:
Do not access gmbus_ports array past its end.

MFC r278159 (by emaste):
Remove duplicate intel_fbc_enabled prototype.

drm: Take vt(4) default mode from loader tunables

By default, vt(4) gets the "preferred mode" from DRM, when using a DRM
video driver as its backend. The preferred mode is usually the native
screen resolution.

Now, if this mode isn't appropriate, a user can use loader tunables to
select a mode. The tunables are read in the following order:
1. kern.vt.fb.modes.$connector_name
2. kern.vt.fb.default_mode

For example, to set a 1024x768 mode, no matter the connector:
kern.vt.fb.default_mode="1024x768"

To set a 800x600 mode only on the laptop builtin screen:
kern.vt.fb.modes.LVDS-1="800x600"

Beside r274031, this MFC includes:

r274049:
drm: When reading connector mode tunables, list connectors

... and their associated tunables. This gives a way to know the list of
available connectors, no matter the driver.

The problem is that xrandr(1) can list connectors but it uses a
different naming.

r274050:
vt(4): Document kern.vt.fb.default_mode and kern.vt.fb.modes.*

Those tunables are used to set a specific mode in vt(4) instead of using
the default mode.

Differential Revision: https://reviews.freebsd.org/D1098
Reviewed by: ak@, emaste@, kwm@

r274051:
vt(4): Improve the description of kern.vt.fb.modes.$connector

Differential Revision: https://reviews.freebsd.org/D1098
Submitted by: emaste@

r274053:
vt(4): Start new sentences on their own lines

Submitted by: brueffer@

MFC of: r274031, r274049, r274050, r274051, r274053

MFC r268981
Remove #ifdef-s to reduce difference to upstream.

Pointed by: kib
Approved by: re (glebius)

Sponsored by: The FreeBSD Foundation

vt(4): Merge several bug fixes and improvements

SVN revisions in this MFC:
269779 270705 270706 271180 271250 271253 271682 271684

Detailed commit list:

r269779:
fbd: Fix a bug where vt_fb_attach() success would be considered a failure

vt_fb_attach() currently always returns 0, but it could return a code
defined in errno.h. However, it doesn't return a CN_* code. So checking
its return value against CN_DEAD (which is 0) is incorrect, and in this
case, a success becomes a failure.

The consequence was unimportant, because the caller (drm_fb_helper.c)
would only log an error message in this case. The console would still
work.

Approved by: nwhitehorn

r270705:
vt(4): Add cngrab() and cnungrab() callbacks

They are used when a panic occurs or when entering a DDB session for
instance.

cngrab() forces a vt-switch to the console window, no matter if the
original window is another terminal or an X session. However, cnungrab()
doesn't vt-switch back to the original window currently.

r270706:
drm: Don't "taskqueue" vt-switch if under DDB/panic situation

If DDB is active, we can't use a taskqueue thread to switch away from
the X window, because this thread can't run.

Reviewed by: ray@
Approved by: ray@

r271180:
vt_vga: vd_setpixel_t and vd_drawrect_t are noop in text mode

r271250:
vt(4): Change the terminal and buffer sizes, even without a font

This fixes a bug where scroll lock would not work for tty #0 when using
vt_vga's textmode. The reason was that this window is created with a
static 256x100 buffer, larger than the real size of 80x25.

Now, in vt_change_font() and vt_compute_drawable_area(), we still
perform operations even of the window has no font loaded (this is the
case in textmode here vw->vw_font == NULL). One of these operation
resizes the buffer accordingly.

In vt_compute_drawable_area(), we take the terminal size as is (ie.
80x25) for the drawable area.

The font argument to vt_set_border() is removed (it was never used) and
the code now uses the computed drawable area instead of re-doing its own
calculation.

Reported by: Harald Schmalzbauer <h.schmalzbauer_omnilan.de>
Tested by: Harald Schmalzbauer <h.schmalzbauer_omnilan.de>

r271253:
pause_sbt(): Take the cold path (ie. use DELAY()) if KDB is active

This fixes a panic in the i915 driver when one uses debug.kdb.enter=1
under vt(4).

PR: 193269
Reported by: emaste@
Submitted by: avg@

r271682:
vt(4): Fix a LOR which occurs during a call to vt_upgrade()

Reported by: kib@
Review: https://reviews.freebsd.org/D785
Reviewed by: ray@
Approved by: ray@

r271684:
vt(4): Use vt_fb_drawrect() and vt_fb_setpixel() in all vt_fb-derivative

Review: https://reviews.freebsd.org/D789
Reviewed by: nwhitehorn
Approved by: nwhitehorn

Approved by: re (gjb)

MFC 259016,259019,259049,259071,259102,259110,259129,259130,259178,259179,
259203,259221,259261,259532,259615,259650,259651,259667,259680,259727,
259761,259772,259776,259777,259830,259882,259915,260160,260449,260450,
260688,260888,260953,261269,261547,261551,261552,261553,261585:
Merge the vt(4) driver (newcons) to stable/10.

Approved by: ray

drm: Update the device-independent code to match Linux 3.8.13

This update brings few features:
o Support for the setmaster/dropmaster ioctls. For instance, they
are used to run multiple X servers simultaneously.
o Support for minor devices. The only user-visible change is a new
entry in /dev/dri but it is useless at the moment. This is a
first step to support render nodes [1].

The main benefit is to greatly reduce the diff with Linux (at the
expense of an unreadable commit diff). Hopefully, next upgrades will be
easier.

No updates were made to the drivers, beside adapting them to API
changes.

[1] https://en.wikipedia.org/wiki/Direct_Rendering_Manager#Render_nodes

r280814 is merged at the same time to avoid a short window where RANDR
might be broken:

drm: Import Linux commit 9bc3cd5673d84d29272fa7181a4dfca83cbb48c1

Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date: Fri May 31 12:17:08 2013 +0000

drm: Sort connector modes based on vrefresh

Keeping the modes sorted by vrefresh before the pixel clock makes the
mode list somehow more pleasing to the eye.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

PR: 198936 (r280814)
Tested by: Many people
MFC of: r280183, r280187 (original commit by glebius), r280814
Relnotes: yes

MFC r277487:
An update for the i915 GPU driver, which brings the code up to Linux
commit 4d93914ae3db4a897ead4b.

MFC r277959 (by adrian):
Fix backlight for ivybridge based laptops (and whatever else comes through
this codepath.)

MFC r278146:
Do not attach to the unsupported chipsets, unless magic tunable is
frobbed.

MFC r278147, r278148:
Fix sign for the error code returned from the driver-specific code.

MFC r278152:
Do not access gmbus_ports array past its end.

MFC r278159 (by emaste):
Remove duplicate intel_fbc_enabled prototype.

drm: Take vt(4) default mode from loader tunables

By default, vt(4) gets the "preferred mode" from DRM, when using a DRM
video driver as its backend. The preferred mode is usually the native
screen resolution.

Now, if this mode isn't appropriate, a user can use loader tunables to
select a mode. The tunables are read in the following order:
1. kern.vt.fb.modes.$connector_name
2. kern.vt.fb.default_mode

For example, to set a 1024x768 mode, no matter the connector:
kern.vt.fb.default_mode="1024x768"

To set a 800x600 mode only on the laptop builtin screen:
kern.vt.fb.modes.LVDS-1="800x600"

Beside r274031, this MFC includes:

r274049:
drm: When reading connector mode tunables, list connectors

... and their associated tunables. This gives a way to know the list of
available connectors, no matter the driver.

The problem is that xrandr(1) can list connectors but it uses a
different naming.

r274050:
vt(4): Document kern.vt.fb.default_mode and kern.vt.fb.modes.*

Those tunables are used to set a specific mode in vt(4) instead of using
the default mode.

Differential Revision: https://reviews.freebsd.org/D1098
Reviewed by: ak@, emaste@, kwm@

r274051:
vt(4): Improve the description of kern.vt.fb.modes.$connector

Differential Revision: https://reviews.freebsd.org/D1098
Submitted by: emaste@

r274053:
vt(4): Start new sentences on their own lines

Submitted by: brueffer@

MFC of: r274031, r274049, r274050, r274051, r274053

MFC r268981
Remove #ifdef-s to reduce difference to upstream.

Pointed by: kib
Approved by: re (glebius)

Sponsored by: The FreeBSD Foundation

vt(4): Merge several bug fixes and improvements

SVN revisions in this MFC:
269779 270705 270706 271180 271250 271253 271682 271684

Detailed commit list:

r269779:
fbd: Fix a bug where vt_fb_attach() success would be considered a failure

vt_fb_attach() currently always returns 0, but it could return a code
defined in errno.h. However, it doesn't return a CN_* code. So checking
its return value against CN_DEAD (which is 0) is incorrect, and in this
case, a success becomes a failure.

The consequence was unimportant, because the caller (drm_fb_helper.c)
would only log an error message in this case. The console would still
work.

Approved by: nwhitehorn

r270705:
vt(4): Add cngrab() and cnungrab() callbacks

They are used when a panic occurs or when entering a DDB session for
instance.

cngrab() forces a vt-switch to the console window, no matter if the
original window is another terminal or an X session. However, cnungrab()
doesn't vt-switch back to the original window currently.

r270706:
drm: Don't "taskqueue" vt-switch if under DDB/panic situation

If DDB is active, we can't use a taskqueue thread to switch away from
the X window, because this thread can't run.

Reviewed by: ray@
Approved by: ray@

r271180:
vt_vga: vd_setpixel_t and vd_drawrect_t are noop in text mode

r271250:
vt(4): Change the terminal and buffer sizes, even without a font

This fixes a bug where scroll lock would not work for tty #0 when using
vt_vga's textmode. The reason was that this window is created with a
static 256x100 buffer, larger than the real size of 80x25.

Now, in vt_change_font() and vt_compute_drawable_area(), we still
perform operations even of the window has no font loaded (this is the
case in textmode here vw->vw_font == NULL). One of these operation
resizes the buffer accordingly.

In vt_compute_drawable_area(), we take the terminal size as is (ie.
80x25) for the drawable area.

The font argument to vt_set_border() is removed (it was never used) and
the code now uses the computed drawable area instead of re-doing its own
calculation.

Reported by: Harald Schmalzbauer <h.schmalzbauer_omnilan.de>
Tested by: Harald Schmalzbauer <h.schmalzbauer_omnilan.de>

r271253:
pause_sbt(): Take the cold path (ie. use DELAY()) if KDB is active

This fixes a panic in the i915 driver when one uses debug.kdb.enter=1
under vt(4).

PR: 193269
Reported by: emaste@
Submitted by: avg@

r271682:
vt(4): Fix a LOR which occurs during a call to vt_upgrade()

Reported by: kib@
Review: https://reviews.freebsd.org/D785
Reviewed by: ray@
Approved by: ray@

r271684:
vt(4): Use vt_fb_drawrect() and vt_fb_setpixel() in all vt_fb-derivative

Review: https://reviews.freebsd.org/D789
Reviewed by: nwhitehorn
Approved by: nwhitehorn

Approved by: re (gjb)

MFC 259016,259019,259049,259071,259102,259110,259129,259130,259178,259179,
259203,259221,259261,259532,259615,259650,259651,259667,259680,259727,
259761,259772,259776,259777,259830,259882,259915,260160,260449,260450,
260688,260888,260953,261269,261547,261551,261552,261553,261585:
Merge the vt(4) driver (newcons) to stable/10.

Approved by: ray