The whole rounding stuff really depends on a specific resolution.

This reverts commit 4dd83942b418b937e3da02746baabf63f37fe682.

Force round down in division calculating required logo height as
preceding code did round up as follows:

logo_lines = DIV_ROUND_UP(logo_height, vc->vc_font.height);

Which resulted in no boot-logo shown at all due to not enough lines
being available.

Additionally disable cursor for custom boot logo.

Using this unconditionally cuts the birds feet (;-p).

This reverts commit 491f263ebfb338c59abfbde6d4e0e7256a0150fa.

Force round down in division calculating required logo height as
preceding code did round up as follows:

logo_lines = DIV_ROUND_UP(logo_height, vc->vc_font.height);

Which resulted in no boot-logo shown at all due to not enough lines
being available.

Don't initialize the whole display controller (dc) when framebuffer
mode is set to off.

This avoids creation of the /dev/tegra_dc_x device. The tegra X
driver requires for each tegra_dc_x device an framebuffer device
with the same id. This patch avoids creation of both, which makes
the tegra X driver load correctly.

Note: Turning off tegrafb0 still leads to kernel crash due to
hard coded device enumeration.

Conflicts:
	drivers/media/video/tegra_v4l2_camera.c
reverted to current driver supporting ACM rather than CSI2
	drivers/media/video/videobuf2-dma-nvmap.c
	drivers/video/tegra/host/Makefile

Hack to avoid 24 Hz mode in X resulting in no display at all. This has
been encountered using e.g. a Samsung SyncMaster F2380 if connected by
HDMI.

root@colibri-t20:~# xrandr
Screen 0: minimum 256 x 128, current 1920 x 1080, maximum 2048 x 2048
LVDS-1 connected 1920x1080+0+0 (normal left inverted right x axis y
axis) 0mm x 0mm
   1920x1080      60.0*+
HDMI-1 connected 1920x1080+0+0 (normal left inverted right x axis y
axis) 160mm x 90mm
   1920x1080      60.0 +   24.0*
   1680x1050      59.9
   1280x1024      75.0     60.0
   1440x900       75.0     59.9
   1280x960       60.0
   1280x800       59.9
   1152x864       75.0
   1280x720       60.0     50.0
   1024x768       75.0     70.1     60.0
   832x624        74.6
   800x600        72.2     75.0     60.3     56.2
   720x576        50.0
   720x480        59.9
   640x480        75.0     72.8     66.7     59.9
   720x400        70.1

This is really just enabling the same hack from Apalis/Colibri T30
which is now relevant on the Colibri T20 as well due to the modedb
changes:

3a6fc5303b9e798295caa01d2cfe75b05fdccf55

Before updating modes on HDMI hotplug, check if framebuffer is
registered at all. This allows to disable framebuffers completely.

Allow to change clock polarity for RGB display output using the
keywords outputen/pixclockpol/vsync and hsync. Add them right
after the driver specification, use 0/1 to specifiy high/low
polarity, e.g. video=tegrafb0:pixclockpol:1,800x480

Remove special clocks for Tegra 2, but use backup clock source
instead. This allows to run all common used resolution within
the drivers -1/+9% allowed band for pixelclock exactness.