Quoting Chris Wilson's more concise description:

"Ah I think I see the problem. As you point out we only mask the current
interrupt received, so that if we have a task pending (and so IMR != 0) we
actually unmask the pending interrupt and so could receive it again before the
tasklet is finally kicked off by the grumpy scheduler."

We need the hw to issue PM interrupts A, B, A while the scheduler is hating us
and refuses to run the rps work item. On receiving PM interrupt A we hit the
WARN because

dev_priv->pm_iir == PM_A | PM_B

Also add a posting read as suggested by Chris to ensure proper ordering of the
writes to PMIMR and PMIIR. Just in case somebody weakens write ordering.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

This is general TMDS detect, not HDMI specifically.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

I can't think of any sensible reason to limit this to a mask of 0x0f,
ie, SDVO_OUTPUT_{TMDS,RGB,CVBS,SVID}0.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

I have no evidence for this byte being used this way, and lots of
counterexamples.  Restore the struct to its empirical definition and
patch up gmbus setup to match.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

Conflicts:
	drivers/gpu/drm/i915/intel_dp.c

Just whitespace change conflicts

If the panel is powered up, there's no need to delay for the 'off'
interval when turning the panel on.
Signed-off-by: Keith Packard <keithp@keithp.com>

This eliminates a fairly long delay when power sequencing newer
hardware
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

There's no good reason to turn off the eDP force VDD bit synchronously
while probing devices; that just sticks a huge delay into all mode
setting paths. Instead, queue a delayed work proc to disable the VDD
force bit and then remember when that fires to ensure that the
appropriate delay is respected before trying to turn it back on.
Signed-off-by: Keith Packard <keithp@keithp.com>

We need to check eDP VDD force and panel on in several places, so
create some simple helper functions to avoid duplicating code.
Signed-off-by: Keith Packard <keithp@keithp.com>

The return value was unused, so just stop doing that.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This value doesn't come directly from the VBT, and so is rather
specific to the particular DP output.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Store the panel power sequencing delays in the dp private structure,
rather than the global device structure. Who knows, maybe we'll get
more than one eDP device in the future.

From the eDP spec, we need the following numbers:

 T1 + T3	Power on to Aux Channel operation (panel_power_up_delay)

		This marks how long it takes the panel to boot up and
		get ready to receive aux channel communications.

 T8		Video signal to backlight on (backlight_on_delay)

		Once a valid video signal is being sent to the device,
		it can take a while before the panel is actuall
		showing useful data. This delay allows the panel
		to get something reasonable up before the backlight
		is turned on.

 T9		Backlight off to video off (backlight_off_delay)

		Turning the backlight off can take a moment, so
		this delay makes sure there is still valid video
		data on the screen.

 T10		Video off to power off (panel_power_down_delay)

		Presumably this delay allows the panel to perform
		an orderly shutdown of the display.

 T11 + T12	Power off to power on (panel_power_cycle_delay)

		So, once you turn the panel off, you have to wait a
		while before you can turn it back on. This delay is
		usually the longest in the entire sequence.

Neither the VBIOS source code nor the hardware documentation has a
clear mapping between the delay values they provide and those required
by the eDP spec. The VBIOS code actually uses two different labels for
the delay values in the five words of the relevant VBT table.

**** MORE LATER ***

Look at both the current hardware register settings and the VBT
specified panel power sequencing timings. Use the maximum of the two
delays, to make sure things work reliably. If there is no VBT data,
then those values will be initialized to zero, so we'll just use the
values as programmed in the hardware. Note that the BIOS just fetches
delays from the VBT table to place in the hardware registers, so we
should get the same values from both places, except for rounding.

VBT doesn't provide any values for T1 or T2, so we'll always just use
the hardware value for that.

The panel power up delay is thus T1 + T2 + T3, which should be
sufficient in all cases.

The panel power down delay is T1 + T2 + T12, using T1+T2 as a proxy
for T11, which isn't available anywhere.

For the backlight delays, the eDP spec says T6 + T8 is the delay from the
end of link training to backlight on and T9 is the delay from
backlight off until video off. The hardware provides a 'backlight on'
delay, which I'm taking to be T6 + T8 while the VBT provides something
called 'T7', which I'm assuming is s

On the macbook air I'm testing with, this yields a power-up delay of
over 200ms and a power-down delay of over 600ms. It all works now, but
we're frobbing these power controls several times during mode setting,
making the whole process take an awfully long time.
Signed-off-by: Keith Packard <keithp@keithp.com>

Any call to intel_dp_sink_dpms must ensure that the panel has power so
that the DP_SET_POWER operation will be correctly received. The only
one missing this was in intel_dp_prepare.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The DP i2c initialization code does a couple of i2c transactions,
which means that an eDP panel must be powered up.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Talking to the eDP DDC channel requires that the panel be powered
up. Wrap both the EDID and modes fetch code with calls to turn the vdd
power on and back off.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

On eDP, DDC requires panel power, but turning that on uses the panel
power sequencing timing values fetch from the DPCD data.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

If the panel is already off, we'll need to turn VDD on to execute the
(useless) DPMS off code. Yes, it would be better to just not do any of
this, but correctness, and *then* performance.
Signed-off-by: Keith Packard <keithp@keithp.com>

The VDD force bit is turned on before touching the panel, but if it
was enabled, there was no call to turn it back off. Add a call.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Cleans up code dealing with eDP a bit. Remove redundant checks in
callers
Signed-off-by: Keith Packard <keithp@keithp.com>

Avoid any question about locked registers by just writing the unlock
pattern with every write to the register.
Signed-off-by: Keith Packard <keithp@keithp.com>

Verify that the eDP VDD is on, either with the panel being on or with
the VDD force-on bit being set.

This demonstrates that in many instances, VDD is not on when needed,
which leads to failed EDID communications.
Signed-off-by: Keith Packard <keithp@keithp.com>

We're going to assume that EDID is more reliable than the VBT tables
for eDP panels, which is notably true on MacBook machines where the
VBT contains completely bogus data.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This masks out all interrupts and ack's any pending ones at IRQ
uninstall time to make sure we don't receive any unexpected interrupts
later on.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

We were relying on the BIOS to set these bits, which doesn't always
happen.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The reference clock configuration must be done before any mode setting
can occur as all outputs must be disabled to change
anything. Initialize the clocks after turning everything off during
the initialization process.

Also, re-initialize the refclk at resume time.
Signed-off-by: Keith Packard <keithp@keithp.com>

I can't find any reference clocks which run at 96MHz as seems to be
indicated from the comments in this code.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

When trying to use SSC on Ibex Peak without CK505, any non-SSC outputs
(like VGA or TV) get broken. So, do not use SSC on Ibex Peak unless
there is a CK505 available (as specified by the VBT).

On Cougar Point, all clocking is internal, so SSC can always be used,
and there will never be a CK505 available.

This eliminates VGA shimmer on some Ironlake machines which have a
CK505 clock source.

References: https://bugzilla.kernel.org/show_bug.cgi?id=21742
References: https://bugs.freedesktop.org/show_bug.cgi?id=38750Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

The PCH refclk settings are global, so we need to look at all of the
encoders, not just the current encoder when deciding how to configure
it. Also, handle systems with more than one panel (any combination of
PCH/non-PCH eDP and LVDS).

Disable SSC clocks when no panels are connected.
Signed-off-by: Keith Packard <keithp@keithp.com>

Allow SSC to be enabled even when the BIOS disables it for testing SSC paths.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

This includes whether an eDP panel is present, and whether that should
use SSC (and at what frequency)
Signed-off-by: Keith Packard <keithp@keithp.com>

This tells the driver whether a CK505 clock source is available on
pre-PCH hardware. If so, it should be used as the non-SSC source,
leaving the internal clock for use as the SSC source.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wison <chris@chris-wilson.co.uk>

These are all KMS related anyways, so don't hide them under other
debug levels.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

Signed-off-by: Keith Packard <keithp@keithp.com>

Make the default FBC behaviour chipset specific, allowing us to turn
it on by default for Ironlake and older where it has been seen to
cause trouble with screen updates.
Signed-off-by: Keith Packard <keithp@keithp.com>
Tested-by: Francis Moreau <francis.moro@gmail.com>

I was seeing a nasty 5 frame glitch every 10 seconds, caused by the
poll for connection on DVI attached by SDVO.

As my SDVO DVI supports hotplug detect interrupts, the fix is to
enable them, and hook them in to the various bits of driver
infrastructure so that they work reliably.

Note that this is only tested on single-function DVI-D SDVOs, on two
platforms (965GME and 945GSE), and has not been checked against a
specification document.

With lots of help from Adam Jackson <ajax@redhat.com> on IRC.
Signed-off-by: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

While I think the previous code is correct, it was hard to follow and
hard to debug. Since we already have a ring abstraction, might as well
use it to handle the semaphore updates and compares.

I don't expect this code to make semaphores better or worse, but you
never know...

v2:
Remove magic per Keith's suggestions.
Ran Daniel's gem_ring_sync_loop test on this.

v3:
Ignored one of Keith's suggestions.

v4:
Removed some bloat per Daniel's recommendation.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Keith Packard <keithp@keithp.com>