According to the DP specification the disparity of the first symbol
should always be negative. It is therefore safe to assume that panels
will conform to that and therefore parameterizing this field should
never be necessary.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Instead of always enabling all four lanes, enable only the number probed
from the link.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Power on only those lanes required for the specified link.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Interlaced mode is currently not supported on the SOR, so don't program
any associated registers.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Use the speed probed from the link at runtime rather than relying on a
hardcoded default.

Signed-off-by: Thierry Reding <treding@nvidia.com>

The number of HBLANK and VBLANK symbols can be computed at runtime so
that they can be set appropriately depending on the video mode and DP
link.

These values are used by the packet generation logic to determine how
many audio samples can be transferred during the blanking intervals.

Signed-off-by: Thierry Reding <treding@nvidia.com>

The currently hardcoded link parameters don't work on all eDP panels, so
compute the parameters at runtime depending on the mode and panel type
to allow the driver to cope with a wider variety of panels.

Note that the number of bits per pixel of the panel is still hardcoded,
but this can be addressed in a separate patch.

This is largely based on a patch by Stéphane Marchesin but the algorithm
was largely rewritten to be more readable and concise.

Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Lanes are powered up in decreasing order. Power them down in increasing
order for consistency.

Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

The comment above mentions link A/B but this isn't what the code does,
so let's fix that.

Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

The code currently rounds up the clock to the next MHZ, which is
rounding up a 69.5MHz clock to 70MHz on my machine. This in turn
prevents the display from syncing. Removing this rounding fixes eDP
for me.

Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>