I noticed this while doing the VMA abstraction. AFAICT, it won't
actually fix anything, but it is the correct thing to do.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The GTT start is either 0 in the KMS case, or some value which is set
only after the init IOCTL in the UMS case. In both cases, we don't have
this information until after we've tried to kick out the firmware fb.

This patch should have no functional change since we kzalloc the GTT
struct anyway. It only clarifies the situation for people who end up
having to look at that code.

This weirdness was introduced in:

commit 93d18799
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Thu Jan 17 12:45:17 2013 -0800

    drm/i915: Remove use of gtt_mappable_entries
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drm_i915_private is getting bigger and bigger when adding new vbt stuff.
So, the better way of getting drm_i915_private organized is to create
a special structure for vbt stuff.

v2: Basically conflicts fixes
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@gmail.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>

Let's introduce one more of those orthogonal feature macros. This should
hopefully make the code more readable and make things easier for new platform
enabling.

This time, HAS_FPGA_DBG_UNCLAIMED() is true for platforms that have bit
31 of FPGA_DBG able to signal unclaimed writes.
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>

This way, when adding a device flag we don't have to manually maintain
that list.

v2: undefine the helper macros (Jani Nikula, Daniel Vetter)
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>

DEV_INFO_FOR_FLAG() now takes 2 parameters:
  • A function to apply to the flag
  • A separator

This will allow us to use the macro twice in the DRM_DEBUG_DRIVER() call
of i915_dump_device_info().

v2: Fix a typo in the subject (Jani Nikula)
v3: Undef the helper macros (Jani Nikula, Daniel vetter)
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This will allow us to read/write registers in GTT init.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Fix up error handling. We really should look into devres for
this stuff ...]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

GEN supports a fusing option which subtracts the PCH display (making the
CPU display also useless). In this configuration MMIO which gets decoded
to a certain range will hang the CPU.

For us, this is sort of the equivalent of having no pipes, and we can
easily modify some code to not do certain things with no pipes.

v2: Moved the num pipes check up in the call chain, and removed extra
checks noted by Daniel. For more details, see:
http://lists.freedesktop.org/archives/intel-gfx/2013-March/025746.html

v3: Drop the intel_setup_overlay check (Daniel)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No constant alpha yet though, that needs a new ioctl and/or property to
get/set.

v2: use drm_plane_format_cpp (Ville)
    fix up vlv_disable_plane, remove IVB bits (Ville)
    remove error path rework (Ville)
    fix component order confusion (Ville)
    clean up platform init (Ville)
    use compute_offset_xtiled (Ville)
v3: fix up more format confusion (Ville)
    update to new page offset function (Ville)
v4: remove incorrect formats from framebuffer_init (Ville)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Requested by Daniel.

v2: Fix incorrect num_pipe settings. (Chris)

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise, if the BIOS did anything wrong, our first I915_{WRITE,READ}
will give us "unclaimed register"  messages.

V2: Even earlier.
V3: Move it to intel_early_sanitize_regs.

Bugzilla: http://bugs.freedesktop.org/show_bug.cgi?id=58897Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

i915 driver needs to do modeset when
1. system resumes from sleep
2. lid is opened

In PM_SUSPEND_MEM state, all the GPEs are cleared when system resumes,
thus it is the i915_resume code does the modeset rather than intel_lid_notify().

But in PM_SUSPEND_FREEZE state, this will be broken because
system is still responsive to the lid events.
1. When we close the lid in Freeze state, intel_lid_notify() sets modeset_on_lid.
2. When we reopen the lid, intel_lid_notify() will do a modeset,
   before the system is resumed.
here is the error log,

[92146.548074] WARNING: at drivers/gpu/drm/i915/intel_display.c:1028 intel_wait_for_pipe_off+0x184/0x190 [i915]()
[92146.548076] Hardware name: VGN-Z540N
[92146.548078] pipe_off wait timed out
[92146.548167] Modules linked in: hid_generic usbhid hid snd_hda_codec_realtek snd_hda_intel snd_hda_codec parport_pc snd_hwdep ppdev snd_pcm_oss i915 snd_mixer_oss snd_pcm arc4 iwldvm snd_seq_dummy mac80211 snd_seq_oss snd_seq_midi fbcon tileblit font bitblit softcursor drm_kms_helper snd_rawmidi snd_seq_midi_event coretemp drm snd_seq kvm btusb bluetooth snd_timer iwlwifi pcmcia tpm_infineon i2c_algo_bit joydev snd_seq_device intel_agp cfg80211 snd intel_gtt yenta_socket pcmcia_rsrc sony_laptop agpgart microcode psmouse tpm_tis serio_raw mxm_wmi soundcore snd_page_alloc tpm acpi_cpufreq lpc_ich pcmcia_core tpm_bios mperf processor lp parport firewire_ohci firewire_core crc_itu_t sdhci_pci sdhci thermal e1000e
[92146.548173] Pid: 4304, comm: kworker/0:0 Tainted: G        W    3.8.0-rc3-s0i3-v3-test+ #9
[92146.548175] Call Trace:
[92146.548189]  [<c10378e2>] warn_slowpath_common+0x72/0xa0
[92146.548227]  [<f86398b4>] ? intel_wait_for_pipe_off+0x184/0x190 [i915]
[92146.548263]  [<f86398b4>] ? intel_wait_for_pipe_off+0x184/0x190 [i915]
[92146.548270]  [<c10379b3>] warn_slowpath_fmt+0x33/0x40
[92146.548307]  [<f86398b4>] intel_wait_for_pipe_off+0x184/0x190 [i915]
[92146.548344]  [<f86399c2>] intel_disable_pipe+0x102/0x190 [i915]
[92146.548380]  [<f8639ea4>] ? intel_disable_plane+0x64/0x80 [i915]
[92146.548417]  [<f8639f7c>] i9xx_crtc_disable+0xbc/0x150 [i915]
[92146.548456]  [<f863ebee>] intel_crtc_update_dpms+0x5e/0x90 [i915]
[92146.548493]  [<f86437cf>] intel_modeset_setup_hw_state+0x42f/0x8f0 [i915]
[92146.548535]  [<f8645b0b>] intel_lid_notify+0x9b/0xc0 [i915]
[92146.548543]  [<c15610d3>] notifier_call_chain+0x43/0x60
[92146.548550]  [<c105d1e1>] __blocking_notifier_call_chain+0x41/0x80
[92146.548556]  [<c105d23f>] blocking_notifier_call_chain+0x1f/0x30
[92146.548563]  [<c131a684>] acpi_lid_send_state+0x78/0xa4
[92146.548569]  [<c131aa9e>] acpi_button_notify+0x3b/0xf1
[92146.548577]  [<c12df56a>] ? acpi_os_execute+0x17/0x19
[92146.548582]  [<c12e591a>] ? acpi_ec_sync_query+0xa5/0xbc
[92146.548589]  [<c12e2b82>] acpi_device_notify+0x16/0x18
[92146.548595]  [<c12f4904>] acpi_ev_notify_dispatch+0x38/0x4f
[92146.548600]  [<c12df0e8>] acpi_os_execute_deferred+0x20/0x2b
[92146.548607]  [<c1051208>] process_one_work+0x128/0x3f0
[92146.548613]  [<c1564f73>] ? common_interrupt+0x33/0x38
[92146.548618]  [<c104f8c0>] ? wake_up_worker+0x30/0x30
[92146.548624]  [<c12df0c8>] ? acpi_os_wait_events_complete+0x1e/0x1e
[92146.548629]  [<c10524f9>] worker_thread+0x119/0x3b0
[92146.548634]  [<c10523e0>] ? manage_workers+0x240/0x240
[92146.548640]  [<c1056e84>] kthread+0x94/0xa0
[92146.548647]  [<c1060000>] ? ftrace_raw_output_sched_stat_runtime+0x70/0xf0
[92146.548652]  [<c15649b7>] ret_from_kernel_thread+0x1b/0x28
[92146.548658]  [<c1056df0>] ? kthread_create_on_node+0xc0/0xc0

three different modeset flags are introduced in this patch
MODESET_ON_LID_OPEN: do modeset on next lid open event
MODESET_DONE:  modeset already done
MODESET_SUSPENDED:  suspended, only do modeset when system is resumed

In this way,
1. when lid is closed, MODESET_ON_LID_OPEN is set so that
   we'll do modeset on next lid open event.
2. when lid is opened, MODESET_DONE is set
   so that duplicate lid open events will be ignored.
3. when system suspends, MODESET_SUSPENDED is set.
   In this case, we will not do modeset on any lid events.

Plus, locking mechanism is also introduced to avoid racing.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The idea, and much of the code came originally from:

commit 0712f0249c3148d8cf42a3703403c278590d4de5
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Fri Jan 18 17:23:16 2013 -0800

    drm/i915: Create a vtable for i915 gtt

Daniel didn't like the color of that patch series, and so I asked him to
start something which appealed to his sense of color. The preceding
patches are those, and now this is going on top of that.

[extracted from the original commit message]

One immediately obvious thing to implement is our gmch probing. The init
function was getting massively bloated. Fundamentally, all that's needed
from GMCH probing is the GTT size, and the stolen size. It makes design
sense to put the mappable calculation in there as well, but the code
turns out a bit nicer without it (IMO)

The intel_gtt bridge thing is still here, but the subsequent patches
will finish ripping that out.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Bikeshedded one comment (GMADR is just the PCI aperture, we
use it for other things than just accessing tiled surfaces through a
linear view) and cut the newly added long lines a bit. Also one
checkpatch error.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This has been sprinkled all over the place in dev_priv. I think
it'd be good to also move all the code into a separate file like
i915_gem_error.c, but that's for another patch.
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Mappable_end, ie. size is almost always what you want as opposed to the
number of entries. Since we already have that information, we can scrap
the number of entries and only calculate it when needed.

If gtt_start is !0, this will have slightly different behavior. This
difference can only occur in DRI1, and exists when we try to kick out
the firmware fb. The new code seems like a bugfix to me.

The other case where we've changed the behavior is during init we check
the mappable region against our current known upper and lower limits
(64MB, and 512MB). This now matches the comment, and makes things more
convenient after removing gtt_mappable_entries.

Also worth noting is the setting of mappable_end is taken out of setup
because we do it earlier now in the DRI2 case and therefore need to add
that tiny hunk to support the DRI1 IOCTL.

v2: Move up mappable end to before legacy AGP init

v3: Add the dev_priv inclusion here from previous rebase error in patch
5

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com> (v2)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: squash in fix for a printk format flag mismatch warning.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have enough info to not use the intel_gtt bridge stuff.

v2: Move setup of mappable_base above the legacy init stuff because we
still need that on older platforms. (Daniel)

v3: Remove the dev_priv hunk which was rebased in by accident

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com> (v2)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The purpose of the gtt structure is to help isolate our gtt specific
properties from the rest of the code (in doing so it help us finish the
isolation from the AGP connection).

The following members are pulled out (and renamed):
gtt_start
gtt_total
gtt_mappable_end
gtt_mappable
gtt_base_addr
gsm

The gtt structure will serve as a nice place to put gen specific gtt
routines in upcoming patches. As far as what else I feel belongs in this
structure: it is meant to encapsulate the GTT's physical properties.
This is why I've not added fields which track various drm_mm properties,
or things like gtt_mtrr (which is itself a pretty transient field).
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
[Ben modified commit messages]
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Using copywinwin10 as an example that is dependent upon emitting a lot
of relocations (2 per operation), we see improvements of:

c2d/gm45: 618000.0/sec to 623000.0/sec.
i3-330m: 748000.0/sec to 789000.0/sec.

(measured relative to a baseline with neither optimisations applied).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Userspace is able to hint to the kernel that its command stream and
auxiliary state buffers already hold the correct presumed addresses and
so the relocation process may be skipped if the kernel does not need to
move any buffers in preparation for the execbuffer. Thus for the common
case where the allotment of buffers is static between batches, we can
avoid the overhead of individually checking the relocation entries.

Note that this requires userspace to supply the domain tracking and
requests for workarounds itself that would otherwise be computed based
upon the relocation entries.

Using copywinwin10 as an example that is dependent upon emitting a lot
of relocations (2 per operation), we see improvements of:

c2d/gm45: 618000.0/sec to 632000.0/sec.
i3-330m: 748000.0/sec to 830000.0/sec.

(measured relative to a baseline with neither optimisations applied).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NImre Deak <imre.deak@intel.com>
[danvet: Fixup merge conflict in userspace header due to different
baseline trees.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to clean up the overlay first, before taking down the
stolen memory allocator.

This regression has been introducec in

commit 80405138
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Nov 15 11:32:29 2012 +0000

    drm/i915: Allocate overlay registers from stolen memory

v2: Rework the patch a bit as suggested by Chris Wilson:
- move the overlay teardown up, into the modeset cleanup
- move the stolen mm takedown into i915_gem_cleanup_stolen

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

Now that Chris Wilson demonstrated that the key for stability on early
gen 2 is to simple _never_ exchange the physical backing storage of
batch buffers I've tried a stab at a kernel solution. Doesn't look too
nefarious imho, now that I don't try to be too clever for my own good
any more.

v2: After discussing the various techniques, we've decided to always blit
batches on the suspect devices, but allow userspace to opt out of the
kernel workaround assume full responsibility for providing coherent
batches. The principal reason is that avoiding the blit does improve
performance in a few key microbenchmarks and also in cairo-trace
replays.
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet:
- Drop the hunk which uses HAS_BROKEN_CS_TLB to implement the ring
  wrap w/a. Suggested by Chris Wilson.
- Also add the ACTHD check from Chris Wilson for the error state
  dumping, so that we still catch batches when userspace opts out of
  the w/a.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Spinning for up to 200 us with interrupts locked out is not good. So
let's just spin (and even that seems to be excessive).

And we don't call these functions from interrupt context, so this is
not required. Besides that doing anything in interrupt contexts which
might take a few hundred us is a no-go. So just convert the entire
thing to a mutex. Also move the mutex-grabbing out of the read/write
functions (add a WARN_ON(!is_locked)) instead) since all callers are
nicely grouped together.

Finally the real motivation for this change: Dont grab the modeset
mutex in the dpio debugfs file, we don't need that consistency. And
correctness of the dpio interface is ensured with the dpio_lock.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For GMCH platforms we set up the hpd irq registers in the irq
postinstall hook. But since we only enable the irq sources we actually
need in PORT_HOTPLUG_EN/STATUS, taking dev_priv->hotplug_supported_mask
into account, no hpd interrupt sources is enabled since

commit 52d7eced
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Sat Dec 1 21:03:22 2012 +0100

    drm/i915: reorder setup sequence to have irqs for output setup

Wrongly set-up interrupts also lead to broken hw-based load-detection
on at least GM45, resulting in ghost VGA/TV-out outputs.

To fix this, delay the hotplug register setup until after all outputs
are set up, by moving it into a new dev_priv->display.hpd_irq_callback.
We might also move the PCH_SPLIT platforms to such a setup eventually.

Another funny part is that we need to delay the fbdev initial config
probing until after the hpd regs are setup, for otherwise it'll detect
ghost outputs. But we can only enable the hpd interrupt handling
itself (and the output polling) _after_ that initial scan, due to
massive locking brain-damage in the fbdev setup code. Add a big
comment to explain this cute little dragon lair.

v2: Encapsulate all the fbdev handling by wrapping the move call into
intel_fbdev_initial_config in intel_fb.c. Requested by Chris Wilson.

v3: Applied bikeshed from Jesse Barnes.

v4: Imre Deak noticed that we also need to call intel_hpd_init after
the drm_irqinstall calls in the gpu reset and resume paths - otherwise
hotplug will be broken. Also improve the comment a bit about why
hpd_init needs to be called before we set up the initial fbdev config.

Bugzilla: Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54943Reported-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org> (v3)
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

At least on the platforms that have a dp aux irq and also have it
enabled - vlvhsw should have one, too. But I don't have a machine to
test this on. Judging from docs there's no dp aux interrupt for gm45.

Also, I only have an ivb cpu edp machine, so the dp aux A code for
snb/ilk is untested.

For dpcd probing when nothing is connected it slashes about 5ms of cpu
time (cpu time is now negligible), which agrees with 3 * 5 400 usec
timeouts.

A previous version of this patch increases the time required to go
through the dp_detect cycle (which includes reading the edid) from
around 33 ms to around 40 ms. Experiments indicated that this is
purely due to the irq latency - the hw doesn't allow us to queue up
dp aux transactions and hence irq latency directly affects throughput.
gmbus is much better, there we have a 8 byte buffer, and we get the
irq once another 4 bytes can be queued up.

But by using the pm_qos interface to request the lowest possible cpu
wake-up latency this slowdown completely disappeared.

Since all our output detection logic is single-threaded with the
mode_config mutex right now anyway, I've decide not ot play fancy and
to just reuse the gmbus wait queue. But this would definitely prep the
way to run dp detection on different ports in parallel

v2: Add a timeout for dp aux transfers when using interrupts - the hw
_does_  prevent this with the hw-based 400 usec timeout, but if the
irq somehow doesn't arrive we're screwed. Lesson learned while
developing this ;-)

v3: While at it also convert the busy-loop to wait_for_atomic, so that
we don't run the risk of an infinite loop any more.

v4: Ensure we have the smallest possible irq latency by using the
pm_qos interface.

v5: Add a comment to the code to explain why we frob pm_qos. Suggested
by Chris Wilson.

v6: Disable dp irq for vlv, that's easier than trying to get at docs
and hw.

v7: Squash in a fix for Haswell that Paulo Zanoni tracked down - the
dp aux registers aren't at a fixed offset any more, but can be on the
PCH while the DP port is on the cpu die.

Reviewed-by: Imre Deak <imre.deak@intel.com> (v6)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise the new&shiny irq-driven gmbus and dp aux code won't work that
well. Noticed since the dp aux code doesn't have an automatic fallback
with a timeout (since the hw provides for that already).

v2: Simple move drm_irq_install before intel_modeset_gem_init, as
suggested by Ben Widawsky.

v3: Now that interrupts are enabled before all connectors are fully
set up, we might fall over serving a HPD interrupt while things are
still being set up. Instead of jumping through massive hoops and
complicating the code with a separate hpd irq enable step, simply
block out the hotplug work item from doing anything until things are
in place.

v4: Actually, we can enable hotplug processing only after the fbdev is
fully set up, since we call down into the fbdev from the hotplug work
functions. So stick the hpd enabling right next to the poll helper
initialization.

v5: We need to enable irqs before intel_modeset_init, since that
function sets up the outputs.

v6: Fixup cleanup sequence, too.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

... together with all the other irq related resources in
intel_irq_init. I've managed to oops in the notify_ring function on my
ilk, presumably because of the powerctx setup call to i915_gpu_idle.

Note that this is only a problem with the reorder irq setup sequence
for irq-driver gmbus/dp aux.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

From BSpec:
"If the Ring Buffer Head Pointer and the Tail Pointer are on the same
cacheline, the Head Pointer must not be greater than the Tail
Pointer."

The easiest way to enforce this is to reduce the reported ring space.

References:
Gen2 BSpec "1. Programming Environment" / 1.4.4.6 "Ring Buffer Use"
Gen3 BSpec "vol1c Memory Interface Functions" / 2.3.4.5 "Ring Buffer Use"
Gen4+ BSpec "vol1c Memory Interface and Command Stream" / 5.3.4.5 "Ring Buffer Use"

v2: Include the exact BSpec references in the description

v3: s/64/I915_RING_FREE_SPACE, and add the BSpec information to the code
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 primary purpose of this was to debug some use-after-free memory
corruption that was causing an OOPS inside drm/i915. As it turned out
the corruption was being caused elsewhere and i915.ko as a major user of
many objects was being hit hardest.

Indeed as we do frequent the generic kmalloc caches, dedicating one to
ourselves (or at least naming one for us depending upon the core) aids
debugging our own slab usage.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Replace the wait for the ring to be clear with the more common wait for
the ring to be idle. The principle advantage is one less exported
intel_ring_wait function, and the removal of a hardcoded value.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Dereference dev_priv only after we know it is valid.
Found with smatch.
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

By always setting up the HWS register for both physical and virtual
address variations during render ring we can reduce the number of
different special cases that get set up at varying different times
during module load.

Fixes regression from

commit c630119f
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Oct 17 11:32:57 2012 +0200

    drm/i915: don't save/restore HWS_PGA reg for kms
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As a quick hack we make the old intel_gtt structure mutable so we can
fool a bunch of the existing code which depends on elements in that data
structure. We can/should try to remove this in a subsequent patch.

This should preserve the old gtt init behavior which upon writing these
patches seems incorrect. The next patch will fix these things.

The one exception is VLV which doesn't have the preserved flush control
write behavior. Since we want to do that for all GEN6+ stuff, we'll
handle that in a later patch. Mainstream VLV support doesn't actually
exist yet anyway.

v2: Update the comment to remove the "voodoo"
Check that the last pte written matches what we readback

v3: actually kill cache_level_to_agp_type since most of the flags will
disappear in an upcoming patch

v4: v3 was actually not what we wanted (Daniel)
Make the ggtt bind assertions better and stricter (Chris)
Fix some uncaught errors at gtt init (Chris)
Some other random stuff that Chris wanted

v5: check for i==0 in gen6_ggtt_bind_object to shut up gcc (Ben)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by [v4]: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Make the cache_level -> agp_flags conversion for pre-gen6 a
tad more robust by mapping everything != CACHE_NONE to the cached agp
flag - we have a 1:1 uncached mapping, but different modes of
cacheable (at least on later generations). Suggested by Chris Wilson.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The BIOS shouldn't be touching this memory across suspend/resume, so
just leave it alone.  This saves us ~6ms on resume on my T420 (retested
with write combined PTEs).

v2: change gtt restore default on pre-gen4 (Chris)
    move needs_gtt_restore flag into dev_priv
v3: make sure we restore GTT on resume from hibernate (Daniel)
    use opregion support as the cutoff for restore from resume (Chris)
v4: use a better check for opregion (Chris)
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Kill the needs_gtt_restore indirection and check directly for
OpRegion. Also explain in a comment what's going on.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This allows the power related code to run independently of the rest of
the pipeline, extending the resume and init time improvements into
userspace, which would otherwise have been blocked on the struct mutex
if we were doing PCU communication.

v2: Also convert the locking for the rps sysfs interface.
Suggested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> (v1)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The console lock can be contended, so rather than prevent other drivers
after us from being held up, queue the console suspend into the global
work queue that can happen anytime.  I've measured this to take around
200ms on my T420.  Combined with the ring freq/turbo change, we should
save almost 1/2 a second on resume.

v2: use console_trylock() to try to resume the console immediately (Chris)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: move dev_priv->console_resume_work next to the fbdev
pointer.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Also, move dev_priv->counter there, it's only used in i915_dma.c

And also move the dri1 dungeon at the end of dev_priv where no one
cares about it.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise we may remove the only console for a nomodeset system.

We became more aggressive in our kicking with
commit e188719a
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Jun 12 11:28:17 2012 +0200

    drm/i915: kick any firmware framebuffers before claiming the gtt

Reported-and-tested-by: monnier@iro.umontreal.ca
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54615Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org # v3.6
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With the introduction of per-process GTT space, the hardware designers
thought it wise to also limit the ability to write to MMIO space to only
a "secure" batch buffer. The ability to rewrite registers is the only
way to program the hardware to perform certain operations like scanline
waits (required for tear-free windowed updates). So we either have a
choice of adding an interface to perform those synchronized updates
inside the kernel, or we permit certain processes the ability to write
to the "safe" registers from within its command stream. This patch
exposes the ability to submit a SECURE batch buffer to
DRM_ROOT_ONLY|DRM_MASTER processes.

v2: Haswell split up bit8 into a ppgtt bit (still bit8) and a security
bit (bit 13, accidentally not set). Also add a comment explaining why
secure batches need a global gtt binding.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
[danvet: added hsw fixup.]
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Convert #include "..." to #include <path/...> in drivers/gpu/.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NDave Airlie <airlied@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDave Jones <davej@redhat.com>