So on a bunch of setups we only have 2 fdi lanes available, e.g. hsw
VGA or 3 pipes on ivb. And seemingly a lot of modes don't quite fit
into this, among them the default 1080p mode.

The solution is to dither down the pipe a bit so that everything fits,
which this patch implements.

But ports compute their state under the assumption that the bpp they
pick will be the one selected, e.g. the display port bw computations
won't work otherwise. Now we could adjust our code to again up-dither
to the computed DP link parameters, but that's pointless.

So instead when the pipe needs to adjust parameters we need to retry
the pipe_config computation at the encoder stage. Furthermore we need
to inform encoders that they should not increase bandwidth
requirements if possible. This is required for the hdmi code, which
prefers the pipe to up-dither to either of the two possible hdmi bpc
values.

LVDS has a similar requirement, although that's probably only
theoretical in nature: It's unlikely that we'll ever see an 8bpc
high-res lvds panel (which is required to hit the 2 fdi lane limit).

eDP is the only thing which could increase the pipe_bpp setting again,
even when in the retry-loop. This could hit the WARN. Two reasons for
not bothering:
- On many eDP panels we'll get a black screen if the bpp settings
  don't match vbt. So failing the modeset is the right thing to do.
  But since that also means it's the only way to light up the panel,
  it should work. So we shouldn't be able to hit this WARN.
- There are still opens around the eDP panel handling, and maybe we
  need additional tricks. Before that happens it's imo no use trying
  to be too clever.
Worst case we just need to kill that WARN or maybe fail the compute
config stage if the eDP connector can't get the bpp setting it wants.
And since this can only happen with an fdi link in between and so for
pch eDP panels it's rather unlikely to blow up, if ever.

v2: Rebased on top of a bikeshed from Paulo.

v3: Improve commit message around eDP handling with the stuff
things with Imre.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to multiply the hdmi port dotclock by 1.5x since it's not
really a dotclock, but the 10/8 encoding bitclock divided by 10.

Also add correct limit checks for the dotclock and reject modes which
don't fit. HDMI 1.4 would allow more, but our hw doesn't support that
unfortunately :(

Somehow I suspect 12bpc hdmi output never really worked - we really
need an i-g-t testcase to check all the different pixel modes and
outputs.

v2: Fixup the adjusted port clock handling - we need to make sure that
the fdi link code still gets the real pixelclock.

v3: g4x/vlv don't support 12bpc hdmi output so drop the bogus comment.
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Switch dotclock limit check to <= as suggested by Ville.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This allows us to use all 4 fdi lanes on fdi B when the cpu eDP is
running on pipe C. Yay!

v2: Encapsulate test into a little helper function, as suggested by
Chris Wilson.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This nicely allows us to drop some hacks which have only been used
to work around modeset failures due to lack of fdi lanes.

v2: Implement proper checking for Haswell platforms - the fdi link to
the LPT PCH has only 2 lanes. Note that we already filter out
impossible modes in intel_crt_mode_valid. Unfortunately LPT does not
support 6bpc on the fdi rx, so we can't pull clever tricks to squeeze
in a few more modes.

v2: Rebased on top of Ben Widawsky's num_pipes reorg.

v3: Rebase on top of Ville's pipe debug output ocd rampage.

v4: Fixup rebase fail spotted by Ville.

v5: Fixup rebase fail spotted by Imre Deak. I suck.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Again in preparation to move the configuration checks into the
pipe_config computation stage of the modeset sequence.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that it's split up, we can easily move it around and precompute
the fdi lane configuration.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

And also move the computed m_n values into the pipe_config. This is a
prep step to move the fdi state computation completely into the
prepare phase of the modeset sequence. Which will allow us to handle
fdi link bw constraints in a better way.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Introduce some nice #defines for the FDI lane width fields and put
them to good use. Suggested by Ville.

v3: Fixup the mask vs. shift copy&pasta fail Imre Deak spotted, and
use the shift #define also in the mask.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need this for two reasons:
- Correct handling of shared fdi lanes on ivb with fastboot.
- Handling fdi link bw limits when we only have two fdi lanes by
  dithering down a bit.

Just search&replace in this patch, no functional change at all.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Totally untested due to lack of screens supporting more than 8bpc. But
now we should have closed all holes in our bpp handling, so this
should be safe. The last missing piece was 10bpc support for g4x/vlv,
since we directly use the pipe bpp to feed the display link (and
anyway, only the cpt has any means to have a pipe bpp != the display
link bpp).
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The current code is rather ... ugly. The only thing it managed to pull
off is getting 6bpc on DP working on g4x. Then someone added another
custom hack for 6bpc eDP on vlv. Fix up this entire mess by properly
implementing the PIPECONF-based dither/bpc controls on g4x/vlv.

Note that compared to pch based platforms g4x/vlv don't support 12bpc
modes. g4x is already caught, extend the check for vlv.

The other fixup is to restrict the lvds-specific dithering to early
gen4 devices - g4x should use the pipeconf dither controls. Note that
on gen2/3 the dither control is in the panel fitter even.

v2: Don't enable dithering when the pipe is in 10 bpc mode. Quoting
from Bspec "PIPEACONF - Pipe A Configuration Register, bit 4":

"Programming note: Dithering should only be enabled for 8 bpc or 6
bpc."

v3: Actually drop the old ugly dither code.

v4: Explain in a short comment why g4x/vlv shouldn't dither for 30 bpp
pipes (Jesse).

v5: Also clear the dither type correctly as spotted by Ville.

v6: As Ville pointed out we need to indeed set the dithering both in
the pipeconf register (for DP outputs) and in the LVDS port register
(for LVDS ouputs). Otherwise LVDS panel will not get properly
dithered. The old patch got away with this since it forgot to clear
the LVDS dither bit ...

v7: Remove redundant BPC_MASK clearing, spotted by Ville.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

They can get at the adjusted mode through intel_crtc->config.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We've had our fair share of woes already which showed that we can't
rely on the bpc limits in the EDID for eDP panels without risking
black screens. So now we limit the depth by what the BIOS recommends
in the VBT:

commit 2f4f649a
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Mon Nov 12 14:33:44 2012 +0200

    drm/i915: do not ignore eDP bpc settings from vbt

But that's not enough, since at least the panel on my ASUS Zenbook
Prime here is also unhappy if the bpc is too low. Hence just take the
firmware value and dither to get what flimsy panels want.

Like before we ensure that we don't change the bpp if the firmware
doesn't provide a value, see

commit 9a30a61f
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Mon Nov 12 14:33:45 2012 +0200

    drm/i915: do not default to 18 bpp for eDP if missing from VBT

v2: Apparently there are some horribly broken eDP panels around which
only work if the DP link is set up as if we want to driver a 24bpp
mode, but still only work if the data is feed at 18bpp. See

commit 57c21963
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Apr 4 17:19:37 2013 +0200

    drm/i915: revert eDP bpp clamping code changes

for the gory details.

Adjust the patch accordingly and update all the relevant comments.

v3: Give up on the cargo-culting v2 attempt and just enfore the edp
bpp value if it's there. Broken panels be damned!

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Tested-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This hack is getting a bit messy, but this plugs the leak for now
until we have the cpu_transcoder properly pipe_config'ed.

Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Instead of repeatedly bombarding the user with a request to reboot and
increase the stolen size with every fb refresh, just inform them the
first time only.

v2: Rearrange code so the hint to increase the amount of memory stolen
by the BIOS is only emitted if we fail to find sufficient stolen memory
for FBC.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: Fixup formatting code mismatch that gcc spotted.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We prevent invalid ones from getting here in the first place, but it
doesn't hurt to have an extra sanity check.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

And put the pfit stuff into substructs while we're at it.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This gets the panel fitter working on eDP on VLV, and should also apply
to eDP panels on G4x chipsets (if we ever detect and mark an all-in-one
panel as eDP anyway).

A few cleanups are still possible on top of this, for example the LVDS
border control could be placed in the LVDS encoder structure and updated
based on the result of the panel fitter calculation.

Multi-pipe fitting isn't handled correctly either if we ever get a config
that wants to try the panel fitter on more than one output at a time.

v2: use pipe_config for storing pfit values (Daniel)
    add i9xx_pfit_enable function for use by 9xx and VLV (Daniel)
v3: fixup conflicts and lvds_dither check
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: fix up botched conflict resolution from Jesse:
- border = LVDS_BORDER_ENABLE was lost for CENTER scaling
- comment about gen2/3 panel fitter scaling was lost
- dev_priv->lvds_dither reintroduced.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We only ever check whether it's strictly bigger than one, so all the
is_sdvo/is_hdmi checks are redundant. Flatten the code a bit.

Also, s/temp/dpll_md/
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If we compute the pch pll state, we _have_ a pch encoder.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

g4x dplls and ilk+ pch plls have a separate field for the reduced p1
setting, so this restriction does not apply. Only older platforms have
the restriction that the p1 divisors must match.

This unnecessary restriction has been introduced in

commit cec2f356
Author: Sean Paul <seanpaul@chromium.org>
Date:   Tue Jan 10 15:09:36 2012 -0800

    drm/i915: Only look for matching clocks for LVDS downcloc

Note that with lvds the p2 divisors _always_ match for LVDS, and we
don't support auto-downclocking anywhere else. On eDP downclocking
works with separate data m/n settings, using the same link clock.

Cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: NSean Paul <seanpaul@chromium.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Up to now we've relied on the bios to get this right for us. Let's try
out whether our code has improved a bit, since we should dither
always when the output bpp doesn't match the plane bpp.
- gen5+ should be fine, since we only use the bios hint as an upgrade.
- gen4 changes, since here dithering is still controlled in the lvds
  register.
- gen2/3 has implicit dithering depeding upon whether you use 2 or 3
  lvds pairs (which makes sense, since it only supports 8bpc pipe
  outpu configurations).
- hsw doesn't support lvds.

v2: Remove redudant dither setting.

v3: Completly drop reliance on dev_priv->lvds_dither.

v4: Enable dithering on gen2/3 only when we have a 18bpp panel, since
up-dithering to a 24bpp panel is not supported by the hw. Spotted by
Ville.

v5: Also only enable lvds port dithering on gen4 for 18bpp modes. In
practice this only excludes dithering a 10bpc plane down for a 24bpp
lvds panel. Not something we truly care about. Again noticed by Ville.

v6: Actually git add.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With the exception of hsw, which has dedicated DP clocks which run at
the fixed frequency already, and vlv, which doesn't have optmized
pre-defined dp clock parameters (yet).

v2: Ville asked me to elaborate a bit more on the longer-term goals
wrt dpll settings computation:

So ultimately my idea is that in the compute config stage first the crtc
code puts the default platform pll limits into the pipe_config. Then
encoders can either overwrite that limit structure with their own special
stuff (mostly for lvds madness). Or they can pick some or all of the
parameters (e.g. just the p2 switchover on hdmi, or all the clock
parameters for dp/sdvo tv).

Once that's done then the generic crtc code can fill out any missing bits
(using the find_best_pll code) and then try to assign which pll to use (if
it's a platform with shared plls). In the end the modeset could should
simply write the computed stuff into registers and never be able to fail.

Of course there's still a lot of data to be moved into pipe_config to make
this all happen, hence some of the temporary ugliness.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org> (v1)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This was somehow lost in the pipe_config->dpll introduction in

commit f47709a9
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Mar 28 10:42:02 2013 +0100

    drm/i915: create pipe_config->dpll for clock state

While at it, extract a few small helpers for common computations.

v2: Use the newly added helpers more thanks to Ville's trick to
typedef the legacy intel_clock_t as the new-world struct dpll.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need the dpll/fp/fp2 values only when we need a pch pll. So move
them together with the code to acquire such a pll.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Between ivb, hsw and vlv, only Ivybridge has sprites with scaling
capabilities.

Also make max_downscale coherent with that.

v2: Rebase on top of the recent ivb/vlv/hsw sprite scaling fixes.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> (v1)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Make TRANSCODER_EDP handling more explicit. (Imre)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With the previous work asle and gse interrupt handlers should now be
functionally the same. Drop the duplicated code.

v2: Drop intel_opregion_gse_intr() also in the !CONFIG_ACPI path. (Damien)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In theory, the BIOS should not even request these from us now that we
aren't claiming we support these, but when it does anyway, don't pretend it
succeeded. It should be the right thing to do, but might confuse the BIOS.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In theory, this should prevent the BIOS from requesting them from us, and
this should be the right thing.

In practice, this is not always the case, and might surprise the BIOS.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Backlight data and registers are fiddled through LVDS/eDP modeset
enable/disable hooks, backlight sysfs files, asle interrupts, and register
save/restore. Protect the backlight related registers and driver private
fields using a spinlock.

The locking in register save/restore covers a little more than is strictly
necessary, including non-modeset case, for simplicity.

v2: Cover register access, save/restore, i915_read_blc_pwm_ctl() and code
    paths leading there.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In preparation of adding locking to backlight, make max backlight value
(the modulation frequency the PWM duty cycle value must not exceed)
internal to intel_panel.c.

Have intel_panel_set_backlight() accept a caller defined range for level,
and scale input to max backlight value internally.

Clean up intel_panel_get_max_backlight() and usage internally.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The LPT PCH only supports 8bpc, so we need to force the pipe bpp
to the right value.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Prevents black screens when using 30bpp framebuffers on my
HDMI screens here. The DP input on the same screen though reports a
1.4 EDID with the correct 8bpc limit set.

v2: Actually check for the right thing!
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Our rps code relies on the interrupts being off to prevent re-arming
of the work items at inopportune moments.

Also drop the redundant cancel_work for the main rps work,
disable_gt_powersave already takes care of that.

Finally add a WARN_ON to ensure we obey that piece of ordering
constraint. Long term I want to lock down the setup/teardown code in a
similar way to how we painstakingly check modeset sequence constraints
already.

v2: Disable polling after hpd handling is shut down - since Egbert's
hpd irq storm handling the hotplug work can re-arm the polling
handler. Spotted by Jani Nikula.

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We don't want to write reserved regs here, and may want to do other bits
in the future, so split it out.
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Ville noticed this while doing another review; we may as well cancel
this work just to make sure we don't try anything fancy after disabling
the RPS interfaces.
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On VLV, the Punit doesn't automatically drop the GPU to it's minimum
voltage level when entering RC6, so we arm a timer to do it for us from
the RPS interrupt handler.  It'll generally only fire when we go idle
(or if for some reason there's a long delay between RPS interrupts), but
won't be re-armed again until the next RPS event, so shouldn't affect
power consumption after we go idle and it triggers.

v2: use delayed work instead of timer + work queue combo (Ville)
v3: fix up delayed work cancel (must be outside lock) (Daniel)
    fix up delayed work handling func for delayed work (Jesse)
v4: cancel delayed work before RPS shutdown (Jani)
    pass delay not absolute time to mod_delayed_work (Jani)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>