Once we thought we got semaphores working, we disabled kicking the ring
if hangcheck fired whilst waiting upon a ring as it was doing more harm
than good:

commit 4e0e90dc
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Dec 14 13:56:58 2011 +0100

    drm/i915: kicking rings stuck on semaphores considered harmful

However, life is never that easy and semaphores are still causing
problems whereby the value written by one ring (bcs) is not being
propagated to the waiter (rcs). Thus the waiter never wakes up and we
declare the GPU hung, which often has unfortunate consequences, even if
we successfully reset the GPU.

But the GPU is idle as it has completed the work, just didn't notify its
clients. So we can detect the incomplete wait during hang check and
probe the target ring to see if has indeed emitted the breadcrumb seqno
following the work and then and only then kick the waiter.

Based on a suggestion by Ben Widawsky.

v2: cross-check wait with iphdr. fix signaller calculation.

References: https://bugs.freedesktop.org/show_bug.cgi?id=54226Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ben Widawsky <ben@bwidawsk.net>
Acked-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

To avoid this:
[  256.798060] [drm] capturing error event; look for more information
in/sys/kernel/debug/dri/0/i915_error_state

Ben Widawsky identified that this regression has been introduced in

commit 2f86f191
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Mon Jan 28 15:32:15 2013 -0800

    drm/i915: Error state should print /sys/kernel/debug
        ...
    [danvet: split up long line.] <----- he did it
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Pimp commit message with the regression note. Also, order
more brown paper bags, I've run out.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Because the register does not exist on LPT. The interesting fact is
that reading/writing PCH_LVDS on LPT does *not* give us "unclaimed
register" messages, but the register value is always 0.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now it returns false for all platforms unless they're explicitly
listed on the function. There should be no real difference, except for
the fact that it now returns false on Haswell.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We're starting to add many IS_HASWELL checks for the power well code,
so add a HAS_POWER_WELL macro to properly document that we're checking
for hardware that has the power down well.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Resolve conflicts since some converted code was added by
not-yet merged patches.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

So don't read it when we hang the GPU. This solves "unclaimed
register" messages.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Future-proof by adding a gen >= 7 check in addition to the
!IS_HSW check from Paulo's original patch, suggested by Ben.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

So don't read it when capturing the error state. This solves some
"unclaimed register" messages on Haswell when we hang the GPU.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This solves some "unclaimed register" messages when there's a GPU hang
on Haswell.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Add missing IS_VLV check as spotted by Ville Syrjälä.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Our mode set sequence documentation says audio must be disabled first.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Resolve conflict since the first patch in this series isn't
applied yet. Also bikeshed commit message as suggested by Ben.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Even if "power power" is good for grepping.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This clarifies the comment above the access_ok check so a missing
VERIFY_READ doesn't alarm anyone.

v2:
 - rewrote comment, thanks to Chris Wilson
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: add patch history log to commit message.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This replaces the manual read/write routines in debugfs with the common
simple attribute helpers. Doing this gets rid of repeated copy/pasting
of copy_from_user and value formatting code.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Squash in follow-up fix from Kees Cook to fix u64 divides on
32bit platforms.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NMihnea Dobrescu-Balaur <mihneadb@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Allows us to detect eDP panels that may not have the hotplug pin wired up.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It uses the same bit definitions.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Fix up a couple of places where we messed with PCH bits on VLV.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This was omitted from

commit b7884eb4
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Mon Jun 4 11:18:15 2012 +0200

    drm/i915: hold forcewake around ring hw init

which introduced the ->has_force_wake flag.

Note that this only enables the above w/a hack.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Put some interesting stuff into the empty commit message.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

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 error, this represents the state of the currently running context at
the time it was loaded.

Unfortunately, since we're hung and can't switch out the context this
may not tell us too much about the most current state of the context,
but does give clues about what has happened since loading.

Thanks to recent doc updates, we have a little more confidence regarding
what is actually in this memory, and perhaps it will help us gain more
insight into certain bugs. AFAICT, the most interesting info is in the
first page. To save space, we only capture the first page. In the
future, we might want to dump more.

Sample of the relevant part of error state:
render ring --- HW Context = 0x01b20000
[0000] 00000000 1100105f 00002028 ffff0880
[0010] 0000209c feff4040 000020c0 efdf0080
[0020] 00002178 00000001 0000217c 00145855
[0030] 00002310 00000000 00002314 00000000

v2: Move error collection to the ring error code
Change format of dump to not confuse intel_error_decode (Chris)
Put the context error object with the others (Chris)
Don't search bound_list instead of active_list (chris)

v3: extract and flatten context recording (daniel)
checkpatch related fixes for the copypasta in debugfs

v4: bug in v3 (Daniel)
-       if ((ring->id == RCS) && error->ccid)
+       if ((ring->id != RCS) || !error->ccid)

References: https://bugs.freedesktop.org/show_bug.cgi?id=55845
Reviewed-by (v2): Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Bikeshed away the redudant parenthese around ring->id != RCS]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Bits used only on HDMI mode now have HDMI_ prefix instead of SDVO_.
The COLOR_FORMAT bits now have prefixes (and the 12bpc bit is for HDMI
only).

Notice that this patch uncovers a bug on the SDVO code: the
COLOR_RANGE_16_235 bit can only be used if the port is in TMDS mode,
not SDVO mode. This will have to be fixed in a later patch.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since they're all the same register, leave all the #defines at the
same place, organized by Gen and also specify which bits are used by
only a specific port or encoding.

Also remove a few unused duplicates and adjust indentation.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Some HDMI registers can be used for SDVO, so saying "HDMIB" should be
the same as saying "SDVOB" for a given HW generation. This was not
true and led to confusions and even a regression.

Previously we had:
  - SDVO{B,C} defined as the Gen3+ registers
  - HDMI{B,C,D} and PCH_SDVOB defined as the PCH registers

But now:
  - SDVO{B,C} became GEN3_SDVO{B,C} on SDVO code
  - SDVO{B,C} became GEN4_HDMI{B,C} on HDMI code
  - HDMI{B,C,D} became PCH_HDMI{B,C,D}
  - PCH_SDVOB is still the same thing

v2: Rebase (v1 was sent in May 2012).
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Commented out and unneeded.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Actually use num_pages (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Kill the HSW check from the single thread force wake code. HSW
uses MT force wake exclusively these days.

The commit that removed HSW single thread forcewake support:

 commit 36ec8f87
 Author: Daniel Vetter <daniel.vetter@ffwll.ch>
 Date:   Thu Oct 18 14:44:35 2012 +0200

    drm/i915: unconditionally use mt forcewake on hsw/ivb
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Use the number '1' instead of FORCEWAKE_KERNEL when requesting single
thread force wake since there is only one bit in the register. Using
the FORCEWAKE_KERNEL name might give someone the wrong impression.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The MT forcewake ACK register also has a corresponding bit to each of
the bits in the MT forcewake register. Use the define we have for the
bit we care about instead of a hardcoded number.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The code is totally obvious so these comments serve no purpose. What's
worse, one of them was wrong. Just remove them.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The load detection code has moved around at some point, but it left
a comment behind. The code now looks to be different enough to make
the comment stale as well. Just remove it.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The proper use of find_pll() isn't always so easy to determine from the
code itself. Some documentation should help.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

to_user_ptr() simply casts a pointer passed as u64 from user space
to void __user * correctly. Using this lets us get rid of all the
tiresome casts.

The idea came from Chris Wilson <chris@chris-wilson.co.uk>.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

So ditch that if clause from the i8xx pll update code.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

While old platforms had 3 transcoders and 3 pipes (1:1), HSW has
4 transcoders and 3 pipes.
These regs were being used only by HDMI code where pipe is always the same
thing as cpu_transcoder.
This patch allow us to use them for DP, specially for TRANSCODER_EDP.

v2: Adding HSW_TVIDEO_DIP_VSC_DATA to transmit vsc to eDP.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Caching the PIPESTAT enable bits has been deemed pointless. Just
read them from the register itself.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The indentation is getting way too deep. Pull the vblank interupt
handling out to separate functions.

v2: Keep flip_mask handling in the main irq handler and
    flatten {i8xx,i915}_handle_vblank() even further.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Use the gen3 logic for handling page flip interrupts on gen4.

Unfortuantely this kills the stall_check since that looks like it can
easily trigger too early. With the current logic the stall check would
kick in on the first vblank after the flip has been submitted to the
ring. If the CS takes longer than that to process the commands in the
ring, the stall check will cause the page flip to be complete too
early. That doesn't sound like a very good idea. Something better
should be deviced if we still need the stall check. For now, mark
i915_pageflip_stall_check() as unused.

v2: Fix irq enable_mask and add __always_unused (Chris Wilson)

References: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1116587Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If the interrupt handler were to process a previous vblank interrupt and
the following flip pending interrupt at the same time, the page flip
would be completed too soon.

To eliminate this race, check the live pending flip status from the ISR
register before finishing the page flip.

v2: Added a comment explaining the logic (by Chris Wilson)
v3: Fix a typo in the comment
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We still rely on a few LVDS bits, but restoring the enable bit can cause
trouble at this point, so don't.

v2: use the right mask to prevent restore (Daniel)
    conditionalize on KMS support (Denial)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>