This reverts commit 0a0883c8.

this was in my tree by accident, I meant to rebase it out and
didn't realise in time.
Signed-off-by: NDave Airlie <airlied@redhat.com>

This has always used a big hammer, but that hammer is probably
too big, I'm also not sure its necessary but at least this
should be safe.

Should fix: https://bugzilla.kernel.org/show_bug.cgi?id=23592Signed-off-by: NDave Airlie <airlied@redhat.com>

This is a revert of 428d2e82.

This is broken in the same manner as for VGA: trying to write to an
invalid address on the (currently 7-bit) i2c bus.

One notable failure appears to be for MacBooks. The scary part was that
it gave the appearance of working (i.e. reporting the absence of the
panel) on various all-in-one machines with ghost LVDS panels and not
failing for laptops.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NDave Airlie <airlied@linux.ie>
Signed-off-by: NKeith Packard <keithp@keithp.com>

This is a moral revert of 6ec3d0c0.

Following the fix to reset the GMBUS controller after a NAK, we finally
utilize the 0xa0 probe for a CRT connection. And discover that the code
is broken. Shock.

There are a number of issues, but following a key insight from Dave
Airlie, that 0xA0 is an invalid address on a 7-bit bus (though not if we
were to enable 10-bit addressing), and would look like the EDID port
0x50, it is possible to see where the confusion starts.

In short, a write to 0xA0 is accepted by the GMBUS controller which we
interpreted as meaning the existence of a connection (a slave on the
other end of the wire ACKing the write). That was false.

During testing with a broken GMBUS implementation, which never reset an
earlier NAK, this test always reported a NAK and so we proceeded on to
the next test.
Reported-and-tested-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=35904Reported-and-tested-by: NRiccardo Magliocchetti <riccardo.magliocchetti@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=32612Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NDave Airlie <airlied@linux.ie>
Signed-off-by: NKeith Packard <keithp@keithp.com>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

Once a NAK has been asserted by the slave, we need to reset the GMBUS
controller in order to continue. This is done by asserting the Software
Clear Interrupt bit and then clearing it again to restore operations.

If we don't clear the NAK, then all future GMBUS xfers will fail,
including DDC probes and EDID retrieval.

v2: Add some comments as suggested by Keith Packard.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=35781Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>
Tested-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: N"Mengmeng Meng" <mengmeng.meng@intel.com>

During modesetting, we need to wait for the hardware to report
readiness by polling the registers. Normally, we call msleep() between
reads, because some state changes may take a whole vblank or more
to complete. However during a panic, we are in an atomic context and
cannot sleep. Instead, busy spin polling the termination condition.

References: https://bugzilla.kernel.org/show_bug.cgi?id=31772Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>

The LVDS connector should default to connected. We tried our best to
verify the claims of the BIOS that the hardware exists during init(),
and then during detect() we then try to verify that the panel is open.
In the event of an unsuccessful query, we should then always report
that the LVDS panel is connected. This was only the case for gen2/3,
later generations leaked the return value from the panel probe instead.
Reported-and-tested-by: NAlessandro Suardi <alessandro.suardi@gmail.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>

This reverts commit a7a75c8f.

There are two different variations on how Intel hardware addresses the
"Hardware Status Page". One as a location in physical memory and the
other as an offset into the virtual memory of the GPU, used in more
recent chipsets. (The HWS itself is a cacheable region of memory which
the GPU can write to without requiring CPU synchronisation, used for
updating various details of hardware state, such as the position of
the GPU head in the ringbuffer, the last breadcrumb seqno, etc).

These two types of addresses were updated in different locations of code
- one inline with the ringbuffer initialisation, and the other during
device initialisation. (The HWS page is logically associated with
the rings, and there is one HWS page per ring.) During resume, only the
ringbuffers were being re-initialised along with the virtual HWS page,
leaving the older physical address HWS untouched. This then caused a
hang on the older gen3/4 (915GM, 945GM, 965GM) the first time we tried
to synchronise the GPU as the breadcrumbs were never being updated.
Reported-and-tested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reported-by: NJan Niehusmann <jan@gondor.com>
Reported-and-tested-by: NJustin P. Mattock <justinmattock@gmail.com>
Reported-and-tested-by: NMichael "brot" Groh <brot@minad.de>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NZhenyu Wang <zhenyuw@linux.intel.com>

This reverts commit a7a75c8f.

There are two different variations on how Intel hardware addresses the
"Hardware Status Page". One as a location in physical memory and the
other as an offset into the virtual memory of the GPU, used in more
recent chipsets. (The HWS itself is a cacheable region of memory which
the GPU can write to without requiring CPU synchronisation, used for
updating various details of hardware state, such as the position of
the GPU head in the ringbuffer, the last breadcrumb seqno, etc).

These two types of addresses were updated in different locations of code
- one inline with the ringbuffer initialisation, and the other during
device initialisation. (The HWS page is logically associated with
the rings, and there is one HWS page per ring.) During resume, only the
ringbuffers were being re-initialised along with the virtual HWS page,
leaving the older physical address HWS untouched. This then caused a
hang on the older gen3/4 (915GM, 945GM, 965GM) the first time we tried
to synchronise the GPU as the breadcrumbs were never being updated.
Reported-and-tested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reported-by: NJan Niehusmann <jan@gondor.com>
Reported-by: NJustin P. Mattock <justinmattock@gmail.com>
Reported-and-tested-by: NMichael "brot" Groh <brot@minad.de>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Found by gem_stress.

As we perform retirement from a workqueue, it is possible for us to free
and unbind objects after the last close on the device, and so after the
address space has been torn down and reset to NULL:

BUG: unable to handle kernel NULL pointer dereference at 00000054
IP: [<c1295a20>] mutex_lock+0xf/0x27
*pde = 00000000
Oops: 0002 [#1] SMP
last sysfs file: /sys/module/vt/parameters/default_utf8

Pid: 5, comm: kworker/u:0 Not tainted 2.6.38+ #214
EIP: 0060:[<c1295a20>] EFLAGS: 00010206 CPU: 1
EIP is at mutex_lock+0xf/0x27
EAX: 00000054 EBX: 00000054 ECX: 00000000 EDX: 00012fff
ESI: 00000028 EDI: 00000000 EBP: f706fe20 ESP: f706fe18
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Process kworker/u:0 (pid: 5, ti=f706e000 task=f7060d00 task.ti=f706e000)
Stack:
 f5aa3c60 00000000 f706fe74 c107e7df 00000246 dea55380 00000054 f5aa3c60
 f706fe44 00000061 f70b4000 c13fff84 00000008 f706fe54 00000000 00000000
 00012f00 00012fff 00000028 c109e575 f6b36700 00100000 00000000 f706fe90
Call Trace:
 [<c107e7df>] unmap_mapping_range+0x7d/0x1e6
 [<c109e575>] ? mntput_no_expire+0x52/0xb6
 [<c11c12f6>] i915_gem_release_mmap+0x49/0x58
 [<c11c3449>] i915_gem_object_unbind+0x4c/0x125
 [<c11c353f>] i915_gem_free_object_tail+0x1d/0xdb
 [<c11c55a2>] i915_gem_free_object+0x3d/0x41
 [<c11a6be2>] ? drm_gem_object_free+0x0/0x27
 [<c11a6c07>] drm_gem_object_free+0x25/0x27
 [<c113c3ca>] kref_put+0x39/0x42
 [<c11c0a59>] drm_gem_object_unreference+0x16/0x18
 [<c11c0b15>] i915_gem_object_move_to_inactive+0xba/0xbe
 [<c11c0c87>] i915_gem_retire_requests_ring+0x16e/0x1a5
 [<c11c3645>] i915_gem_retire_requests+0x48/0x63
 [<c11c36ac>] i915_gem_retire_work_handler+0x4c/0x117
 [<c10385d1>] process_one_work+0x140/0x21b
 [<c103734c>] ? __need_more_worker+0x13/0x2a
 [<c10373b1>] ? need_to_create_worker+0x1c/0x35
 [<c11c3660>] ? i915_gem_retire_work_handler+0x0/0x117
 [<c1038faf>] worker_thread+0xd4/0x14b
 [<c1038edb>] ? worker_thread+0x0/0x14b
 [<c103be1b>] kthread+0x68/0x6d
 [<c103bdb3>] ? kthread+0x0/0x6d
 [<c12970f6>] kernel_thread_helper+0x6/0x10
Code: 00 e8 98 fe ff ff 5d c3 55 89 e5 3e 8d 74 26 00 ba 01 00 00 00 e8
84 fe ff ff 5d c3 55 89 e5 53 8d 64 24 fc 3e 8d 74 26 00 89 c3 <f0> ff
08 79 05 e8 ab ff ff ff 89 e0 25 00 e0 ff ff 89 43 10 58
EIP: [<c1295a20>] mutex_lock+0xf/0x27 SS:ESP 0068:f706fe18
CR2: 0000000000000054
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>

Detected by scripts/coccinelle/free/kfree.cocci.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>

We always skipped flushing the BLT ring if the request flush did not
include the RENDER domain. However, this neglects that we try to flush
the COMMAND domain after every batch and before the breadcrumb interrupt
(to make sure the batch is indeed completed prior to the interrupt
firing and so insuring CPU coherency). As a result of the missing flush,
incoherency did indeed creep in, most notable when using lots of command
buffers and so potentially rewritting an active command buffer (i.e.
the GPU was still executing from it even though the following interrupt
had already fired and the request/buffer retired).

As all ring->flush routines now have the same preconditions, de-duplicate
and move those checks up into i915_gem_flush_ring().

Fixes gem_linear_blit.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=35284Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: mengmeng.meng@intel.com

Along the fast path for relocation handling, we attempt to copy directly
from the user data structures whilst holding our mutex. This causes
lockdep to warn about circular lock dependencies if we need to pagefault
the user pages. [Since when handling a page fault on a mmapped bo, we
need to acquire the struct mutex whilst already holding the mm
semaphore, it is then verboten to acquire the mm semaphore when already
holding the struct mutex. The likelihood of the user passing in the
relocations contained in a GTT mmaped bo is low, but conceivable for
extreme pathology.] In order to force the mm to return EFAULT rather
than handle the pagefault, we therefore need to disable pagefaults
across the relocation fast path.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Fix up the debug file to report the right frequencies.  On SNB, we program
the PCU with a frequency ratio, which is multiplied by 100MHz on the CPU
side.  But GFX only runs at half that, so report it as such to avoid
confusion.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>

The order of the calls does matter indeed.  Swapping the call order of
intel_dp_destroy() and intel_dp_encoder_destroy() fixes the problem.
This is because i2c_del_adapter unregisters the device which parent is
intel_connector, and connectors are removed in intel_dp_destroy().  Thus
intel_dp_encoder_destroy() must be called before intel_dp_destroy().

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=24822Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>

... even though it was disabled. A mistake in the handling of fence reuse
caused us to skip the vital delay of waiting for the object to finish
rendering before changing the register. This resulted in us changing the
fence register whilst the bo was active and so causing the blits to
complete using the wrong stride or even the wrong tiling. (Visually the
effect is that small blocks of the screen look like they have been
interlaced). The fix is to wait for the GPU to finish using the memory
region pointed to by the fence before changing it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34584
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
[Note for 2.6.38-stable, we need to reintroduce the interruptible passing]
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NDave Airlie <airlied@linux.ie>

A broken implementation of is_pot() prevented the detection of when a
singular pipe was enabled. Eric Anholt pointed out the existence of
is_power_of_2() so use that instead of our broken code!

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=35402Signed-off-by: NYuanhan Liu <yuanhan.liu@intel.com>
Tested-by: xunx.fang@intel.com
Reviewed-by: NKeith Packard <keithp@keithp.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

When i915_gem_retire_requests_ring calls i915_gem_request_remove_from_client,
the client_list for that request may already be removed in i915_gem_release.
So we may call twice list_del(&request->client_list), resulting in an
oops like this report:

[126167.230394] BUG: unable to handle kernel paging request at 00100104
[126167.230699] IP: [<f8c2ce44>] i915_gem_retire_requests_ring+0xd4/0x240 [i915]
[126167.231042] *pdpt = 00000000314c1001 *pde = 0000000000000000
[126167.231314] Oops: 0002 [#1] SMP
[126167.231471] last sysfs file: /sys/devices/LNXSYSTM:00/device:00/PNP0C0A:00/power_supply/BAT1/current_now
[126167.231901] Modules linked in: snd_seq_dummy nls_utf8 isofs btrfs zlib_deflate libcrc32c ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs xfs exportfs reiserfs cryptd aes_i586 aes_generic binfmt_misc vboxnetadp vboxnetflt vboxdrv parport_pc ppdev snd_hda_codec_hdmi snd_hda_codec_conexant snd_hda_intel snd_hda_codec snd_hwdep arc4 snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq uvcvideo videodev snd_timer snd_seq_device joydev iwlagn iwlcore mac80211 snd cfg80211 soundcore i915 drm_kms_helper snd_page_alloc psmouse drm serio_raw i2c_algo_bit video lp parport usbhid hid sky2 sdhci_pci ahci sdhci libahci
[126167.232018]
[126167.232018] Pid: 1101, comm: Xorg Not tainted 2.6.38-6-generic-pae #34-Ubuntu Gateway                          MC7833U /
[126167.232018] EIP: 0060:[<f8c2ce44>] EFLAGS: 00213246 CPU: 0
[126167.232018] EIP is at i915_gem_retire_requests_ring+0xd4/0x240 [i915]
[126167.232018] EAX: 00200200 EBX: f1ac25b0 ECX: 00000040 EDX: 00100100
[126167.232018] ESI: f1a2801c EDI: e87fc060 EBP: ef4d7dd8 ESP: ef4d7db0
[126167.232018]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[126167.232018] Process Xorg (pid: 1101, ti=ef4d6000 task=f1ba6500 task.ti=ef4d6000)
[126167.232018] Stack:
[126167.232018]  f1a28000 f1a2809c f1a28094 0058bd97 f1aa2400 f1a2801c 0058bd7b 0058bd85
[126167.232018]  f1a2801c f1a28000 ef4d7e38 f8c2e995 ef4d7e30 ef4d7e60 c14d1ebc f6b3a040
[126167.232018]  f1522cc0 000000db 00000000 f1ba6500 ffffffa1 00000000 00000001 f1a29214
[126167.232018] Call Trace:

Unfortunately the call trace reported was cut, but looking at debug
symbols the crash is at __list_del, when probably list_del is called
twice on the same request->client_list, as the dereferenced value is
LIST_POISON1 + 4, and by looking more at the debug symbols before
list_del call it should have being called by
i915_gem_request_remove_from_client

And as I can see in the code, it seems we indeed have the possibility
to remove a request->client_list twice, which would cause the above,
because we do list_del(&request->client_list) on both
i915_gem_request_remove_from_client and i915_gem_release

As Chris Wilson pointed out, it's indeed the case:
"(...) I had thought that the actual insertion/deletion was serialised
under the struct mutex and the intention of the spinlock was to protect
the unlocked list traversal during throttling. However, I missed that
i915_gem_release() is also called without struct mutex and so we do need
the double check for i915_gem_request_remove_from_client()."

This change does the required check to avoid the duplicate remove of
request->client_list.

Bugzilla: http://bugs.launchpad.net/bugs/733780
Cc: stable@kernel.org # 2.6.38
Signed-off-by: NHerton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

If the pipe or plane is already enabled, then we do not need to enable
it again and can skip the delay. Similarly if it is already disabled
when we want to disable it, we can also skip it.

This fixes a regression from b24e7179, which caused the LVDS
output on one PineView machine to become corrupt after changing
orientation several times.

References: https://bugs.freedesktop.org/show_bug.cgi?id=34601
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>
Tested-by: mengmeng.meng@intel.com

... as wait_for_vblank (and friends) will do a flush of the MMIO writes
anyway.

References: https://bugs.freedesktop.org/show_bug.cgi?id=34601
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NKeith Packard <keithp@keithp.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>

At least on my HP 2540p this is wrong at bootup, fine
at any other time once a lid event has occured. This is due to
_REG vs _INI ordering in the ACPI tables.
Signed-off-by: NDave Airlie <airlied@redhat.com>

This reverts commit 951f3512

    drm/i915: Do not handle backlight combination mode specially

since this commit introduced other regressions due to untouched LBPC
register, e.g. the backlight dimmed after resume.

In addition to the revert, this patch includes a fix for the original
issue (weird backlight levels) by removing the wrong bit shift for
computing the current backlight level.
Also, including typo fixes (lpbc -> lbpc).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34524Acked-by: NIndan Zupancic <indan@nul.nu>
Reviewed-by: NKeith Packard <keithp@keithp.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Cc: <stable@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

... as if we are only reading from it, we can do that concurrently with
the queue flip.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Some hardware claims to have both an LVDS panel and an eDP output.
Whilst this may be true in a rare case, more often it is just broken
hardware. If we see an eDP device we know that it must be connected and
so we can confirm its existence with a simple probe.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34165
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=24822Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Early gen3 and gen2 chipset do not have the relaxed per-surface tiling
constraints of the later chipsets, so we need to check that the GTT
alignment is correct for the new tiling. If it is not, we need to
rebind.
Reported-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Andi Kleen narrowed his GPU hangs on his Sugar Bay (SNB desktop) rev 09
down to the use of GPU semaphores, and we already know that they appear
broken up to Huron River (mobile) rev 08. (I'm optimistic that disabling
GPU semaphores is simply hiding another bug by the latency and
side-effects of the additional device interaction it introduces...)

However, use of semaphores is a massive performance improvement... Only
as long as the system remains stable. Enable at your peril.
Reported-by: NAndi Kleen <andi-fd@firstfloor.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33921Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Whilst the GT is powered down (rc6), writes to MMADDR are placed in a
FIFO by the System Agent. This is a limited resource, only 64 entries, of
which 20 are reserved for Display and PCH writes, and so we must take
care not to queue up too many writes. To avoid this, there is counter
which we can poll to ensure there are sufficient free entries in the
fifo.

"Issuing a write to a full FIFO is not supported; at worst it could
result in corruption or a system hang."
Reported-and-Tested-by: NMatt Turner <mattst88@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34056Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

This reverts commit c2e0eb16.

As it turns out, userspace already depends upon being able to enable
tiling on existing bo which it promises to be large enough for its
purposes i.e. it will not access beyond the end of the last full-tile
row.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=35016Reported-and-tested-by: NKamal Mostafa <kamal@canonical.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

It's cleaned before saving and re-initialized after restoring.
So don't need to save/restore it. And also new chip has new address
for hardware status page register, don't write to old address.
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

It is trivially computable from the real physical address so no need to
store both.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

On a Thinkpad x61s, I noticed some memory corruption when
plugging/unplugging the external VGA connection. The symptoms are that
4 bytes at the beginning of a page get overwritten by zeroes.
The address of the corruption varies when rebooting the machine, but
stays constant while it's running (so it's possible to repeatedly write
some data and then corrupt it again by plugging the cable).

Further investigation revealed that the corrupted address is
(dev_priv->status_page_dmah->busaddr & 0xffffffff), ie. the beginning of
the hardware status page of the i965 graphics card, cut to 32 bits.

So it seems that for some memory access, the hardware uses only 32 bit
addressing. If the hardware status page is located >4GB, this
corrupts unrelated memory.
Signed-off-by: NJan Niehusmann <jan@gondor.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

This seems to be running stably on my test laptop, so hopefully the
reported hangs where just symptoms of other bugs.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

I stumbled over this magic bit in the gen3 INSTPM:

Bit11 Interrupt-Based AGPBUSY# Enable:

‘0’ = Pending GMCH interrupts will not cause AGPBUSY# assertion.
‘1’ = Pending GMCH interrupts will cause AGPBUSY# assertion and hence
      can cause the CPU to exit C3.  There is no suppression of cacheable
      writes.

Note that in either case in C3 the interrupts are not lost. They will be
forwarded to the ICH when the GMCH is out of C3.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@kernel.org

Using PM latency request turns out to be very fragile and only works for
some systems, depending upon the ACPI implementation. However, I've
stumbled across a promising bit in INSTPM: "Interrupt-Based AGPBUSY#".

This reverts commit b0b544cd.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Userspace has a legitimate requirement to use a delta that points to
outside of the target bo, and so we need to enable this. (As this is an
abi break, albeit a relaxation of the current restrictions, mark the change
with a new flag.)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_irq.c: In function ‘ironlake_irq_postinstall’:
drivers/gpu/drm/i915/i915_irq.c:1618: warning: unused variable ‘pipe’
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

After disabling, we're meant to teardown the bo used for the contexts,
not recurse into ourselves again and preventing module unload.
Reported-and-tested-by: NBen Widawsky <bwidawsk@gmail.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>