While the OLPC display appears to be able to handle either positive
or negative sync, the Display Controller only recognises positive sync.

This brings viafb (for XO-1.5) in line with lxfb (for XO-1) and
fixes a recent regression where the XO-1.5 DCON could no longer be
frozen. Thanks to Florian Tobias Schandinat for helping identify
the fix.

Test case: from a vt,
	echo 1 > /sys/devices/platform/dcon/freeze
should cause the current screen contents to freeze, rather than garbage being
displayed.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: stable@kernel.org

With module.h being implicitly everywhere via device.h, the absence
of explicitly including something for EXPORT_SYMBOL went unnoticed.
Since we are heading to fix things up and clean module.h from the
device.h file, we need to explicitly include these files now.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

This commit replace the function strict_strtoul(becasue commit 33ee3b2e), and check the return value to avoid such warning:

  drivers/video/via/viafbdev.c:1992: warning: ignoring return value of 'kstrtoul', declared with attribute warn_unused_result

Signed-off-by: Wang Shaoyan <wangshaoyan.pt@taobao.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

This patch removes the remaining places where assumptions about the
structure of the modetable were made. Aside from some places where
assumptions are made that certain modes are in the modetable the
only code dealing with the modetable and not just a single mode is
in viamode. This will allow chaniging the modetable and use other
sources for videomodes like the subsystem or EDID.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

This patch removes the need for knowing the modetable structure
within the LCD modesetting function. The magic 60Hz refresh rate was
already there as always the first entry for a resolution was choosen
based on the ascending refresh rate ordering in the modetable.
For all but one this is at least 60Hz, if only higher frequencies
available we choose those like the code before did. The exception is
OLPC but that resolution has only one frequency so we get the same
behaviour there as well.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

This patch splits the hardware initialization out of the modesetting
function which will make it easier to make it conditional and not
require starting from scratch for every mode change, which is
especially annoying in dual framebuffer mode.
This required some minor reordering but it should not influence its
functionality.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

This patch starts to use the information in var for modesetting for
CRT and DVI devices. This is the right thing as it allows us to use
more generic modes than the ones predefined by VIA. We do not yet
allow more generic modes as check_var still limits them to the
predefined ones but with this patch applied it would be really easy
to do so. A problem was VIAs SAMM mode as it has 2 different modes
but just one frame buffer device. This is solved by creating a
pseudo var which contains enough information to use it for
modesetting. Hopefully one day we can use information in var for all
modes that do not involve hardware scaling.
Well I'd like to say that the chance of regressions is low but it is
quite likely that the behaviour in some cases changed especially
when SAMM is involved. I hope we made it better than before in
particular the DVI frequency check was probably broken before and
hopefully works better now.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

As there is only one user we can just insert the formula where
needed. Avoids one lookup in the modetable and
viafb_fill_var_timing_info does no longer depend on the modetable.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

This patch introduces 2 new functions for selecting a single mode
based on hres, vres and refresh rate and changes some uses to use
those. The advantage is that it is less error prone than doing the
selection based on refresh rate everywhere and allows replacing the
modetable structure. This includes a little change that users may
notice: If a refresh rate was given as module parameters but does
not exist in the modetable prior to this patch a refresh rate of 60
was assumed and after this patch the closest supported refresh rate
to the one provided by the user is used.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>