drm/i915: remove useless BUG_ON which caused a regression in 3.5.

starting an old X server causes a kernel BUG since commit 1b50247a8d:

------------[ cut here ]------------
kernel BUG at drivers/gpu/drm/i915/i915_gem.c:3661!
invalid opcode: 0000 [#1] SMP
Modules linked in: snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss uvcvideo
+videobuf2_core videodev videobuf2_vmalloc videobuf2_memops uhci_hcd ath9k mac80211 snd_hda_codec_realtek ath9k_common microcode
+ath9k_hw psmouse serio_raw sg ath cfg80211 atl1c lpc_ich mfd_core ehci_hcd snd_hda_intel snd_hda_codec snd_hwdep snd_pcm rtc_cmos
+snd_timer snd evdev eeepc_laptop snd_page_alloc sparse_keymap

Pid: 2866, comm: X Not tainted 3.5.6-rc1-eeepc #1 ASUSTeK Computer INC. 1005HA/1005HA
EIP: 0060:[<c12dc291>] EFLAGS: 00013297 CPU: 0
EIP is at i915_gem_entervt_ioctl+0xf1/0x110
EAX: f5941df4 EBX: f5940000 ECX: 00000000 EDX: 00020000
ESI: f5835400 EDI: 00000000 EBP: f51d7e38 ESP: f51d7e20
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 8005003b CR2: b760e0a0 CR3: 351b6000 CR4: 000007d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
Process X (pid: 2866, ti=f51d6000 task=f61af8d0 task.ti=f51d6000)
Stack:
 00000001 00000000 f5835414 f51d7e84 f5835400 f54f85c0 f51d7f10 c12b530b
 00000001 c151b139 c14751b6 c152e030 00000b32 00006459 00000059 0000e200
 00000001 00000000 00006459 c159ddd0 c12dc1a0 ffffffea 00000000 00000000
Call Trace:
 [<c12b530b>] drm_ioctl+0x2eb/0x440
 [<c12dc1a0>] ? i915_gem_init+0xe0/0xe0
 [<c1052b2b>] ? enqueue_hrtimer+0x1b/0x50
 [<c1053321>] ? __hrtimer_start_range_ns+0x161/0x330
 [<c10530b3>] ? lock_hrtimer_base+0x23/0x50
 [<c1053163>] ? hrtimer_try_to_cancel+0x33/0x70
 [<c12b5020>] ? drm_version+0x90/0x90
 [<c10ca171>] vfs_ioctl+0x31/0x50
 [<c10ca2e4>] do_vfs_ioctl+0x64/0x510
 [<c10535de>] ? hrtimer_nanosleep+0x8e/0x100
 [<c1052c20>] ? update_rmtp+0x80/0x80
 [<c10ca7c9>] sys_ioctl+0x39/0x60
 [<c1433949>] syscall_call+0x7/0xb
Code: 83 c4 0c 5b 5e 5f 5d c3 c7 44 24 04 2c 05 53 c1 c7 04 24 6f ef 47 c1 e8 6e e0 fd ff c7 83 38 1e 00 00 00 00 00 00 e9 3f ff ff
+ff <0f> 0b eb fe 0f 0b eb fe 8d b4 26 00 00 00 00 0f 0b eb fe 8d b6
EIP: [<c12dc291>] i915_gem_entervt_ioctl+0xf1/0x110 SS:ESP 0068:f51d7e20
---[ end trace dd332ec083cbd513 ]---

The crash happens here in i915_gem_entervt_ioctl() :

    3659          BUG_ON(!list_empty(&dev_priv->mm.active_list));
    3660          BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
 -> 3661          BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
    3662          mutex_unlock(&dev->struct_mutex);

Quoting Chris :
  "That BUG_ON there is silly and can simply be removed. The check is to
   verify that no batches were submitted to the kernel whilst the UMS/GEM
   client was suspended - to which the BUG_ONs are a crude approximation.
   Furthermore, the checks are too late, since it means we attempted to
   program the hardware whilst it was in an invalid state, the BUG_ONs are
   the least of your concerns at that point."

Note that this regression has been introduced in

commit 1b50247a8ddde4af5aaa0e6bc125615372ce6c16
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Apr 24 15:47:30 2012 +0100

    drm/i915: Remove the list of pinned inactive objects

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>
[danvet: Added note about the regressing commit and cc: stable.]
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: paper over a pipe-enable vs pageflip race

I've discovered this on my ivb machine while stress-testing the new
flip_tests. Only harmful effect observed is that the timestamp is a
bit bogus.

Note that this is empirical duct-tape: I've noticed that we seem to
only ever miss the very first vblank irq right after enabling the
pipe. And with this hack applied I couldn't reproduce the failure case
anywhere else any more.

Tested-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
UAPI: (Scripted) Disintegrate arch/sh/include/asm

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
ext3: fix possible non-initialized variable on htree_dirblock_to_tree()

This is a backport of ext4 commit 90b0a9732 which fixes a possible
non-initialized variable on htree_dirblock_to_tree().
Ext3 has the same non initialized variable, but, in any case it will be
initialized by ext3_get_blocks_handle(), which will avoid the bug to be
triggered, but, the non-initialized variable by htree_dirblock_to_tree() is
still a bug.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
ext3: ext3_bread usage audit

This is the ext3 version of the same patch applied to Ext4, where such goal is
to audit the usage of ext3_bread() due a possible misinterpretion of its return
value.

Focused on directory blocks, a NULL value returned from ext3_bread() means a
hole, which cannot exist into a directory inode. It can pass undetected after a
fix in an uninitialized error variable.

The (now) initialized variable into ext3_getblk() may lead to a zero'ed return
value of ext3_bread() to its callers, which can make the caller do not detect
the hole in the directory inode.

This patch creates a new wrapper function ext3_dir_bread() which checks for
holes properly, reports error, and returns EIO in that case.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
ext2: fix return values on parse_options() failure

parse_options() in ext2 should return 0 when parse the mount options fails.

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
ext3: fix return values on parse_options() failure

parse_options() in ext3 should return 0 when parse the mount options fails.

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
quota: Silence warning about PRJQUOTA not being handled in need_print_warning()

PRJQUOTA value of quota type should never reach need_print_warning() since XFS
(which is the only fs which uses that type) doesn't use generic functions
calling this function. Anyway, add PRJQUOTA case to the switch to make gcc
happy.

Signed-off-by: Jan Kara <jack@suse.cz>
drm/i915: Set guardband clipping workaround bit in the right register.

A previous patch, namely:

commit bf97b276ca04cee9ab65ffd378fa8e6aedd71ff6
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Apr 11 20:42:41 2012 +0200

    drm/i915: implement w/a for incorrect guarband clipping

accidentally set bit 5 in 3D_CHICKEN, which has nothing to do with
clipping.  This patch changes it to be set in 3D_CHICKEN3, where it
belongs.

The game "Dante" demonstrates random clipping issues when guardband
clipping is enabled and bit 5 of 3D_CHICKEN3 isn't set.  So the
workaround is actually necessary.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Oliver McFadden <oliver.mcfadden@linux.intel.com>
Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: Disallow preallocation of requests

The intention was to allow the caller to avoid a failure to queue a
request having already written commands to the ring. However, this is a
moot point as the i915_add_request() can fail for other reasons than a
mere allocation failure and those failure cases are more likely than
ENOMEM. So the overlay code already had to handle i915_add_request()
failures, and due to

commit 3bb73aba1ed5198a2c1dfaac4f3c95459930d84a
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jul 20 12:40:59 2012 +0100

    drm/i915: Allow late allocation of request for i915_add_request()

the error handling code in intel_overlay.c was subject to causing
double-frees, as found by coverity.

Rather than further complicate i915_add_request() and callers, realise
the battle is lost and adapt intel_overlay.c to take advantage of the
late allocation of requests.

v2: Handle callers passing in a NULL seqno.
v3: Ditto. This time for sure.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: fixup i915_gem_object_get_page inline helper

Note that just because we have n == MAX elements left, does not imply
that there are only MAX elements left in the scatterlist and so we may
not be on the last chain, and the nth element may in fact be a chain ptr.

This is exercised by the improved hangman tests and the gem_exec_big
test in i-g-t.

This regression has been introduced in

commit 9da3da660d8c19a54f6e93361d147509be3fff84
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jun 1 15:20:22 2012 +0100

   drm/i915: Replace the array of pages with a scatterlist

v2: KISS, replace the direct lookup with a for_each_sg() [danvet]
v3: Try to be clever again.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: disable wc gtt pte mappings on gen2

It doesn't work since the gtt pte range sits in the middle of the mmio
bar. We didn't notice that since both my and Chris' gen2 machines
don't support PAT and hence all wc io mapping request will
automatically be demoted to uc.

This regression has been introduce in

commit edef7e685da05c13cce50c0126189c80fe2c8f71
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Sep 14 11:57:47 2012 +0100

    agp/intel: Use a write-combining map for updating PTEs

Reported-by: Egbert Eich <eich@pdx.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=55834
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: rip out the pipe A quirk for i855gm

This seems to be the root-cause that breaks resume on my i855gm when I
apply the "drm/i915: fixup the plane->pipe fixup code" patch. And that
code doesn't even run on my machine, so it's pure timing changes
causing the regression.

Furthermore resume has been constantly switching between working and
broken on this machine ever since kms support has been merged,
seemingly with no related change as a root cause. And always with the
same symptoms of the backlight lighting up, but the lvds panel only
displaying black.

Also, of both i855gm variants only one is in the table. And in the
past we've only ever removed entries from this quirk table because it
breaks things.

So let's just remove it - in case there's indeed a bios out there
relying on a running pipe A, we can add back in a more precise quirk
entry, like all the others (save for i830/i845).

Tested-by: Chris Wilson <chris@chris-wilson.co.uk> #855gm
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: fixup the plane->pipe fixup code

We need to check whether the _other plane is on our pipe, not whether
our plane is on the other pipe. Otherwise if not both pipes/planes are
active, we won't properly clean up the mess and set up our desired
plane->pipe mapping.

v2: Fixup the logic, I've totally fumbled it. Noticed by Chris Wilson.

v3: I've checked Bspec, and the flexible plane->pipe mapping is a
gen2/3 feature, so test for that instead of PCH_SPLIT

v4: Check whether we indeed have 2 pipes before checking the other
pipe, to avoid upsetting i845g/i865g. Noticed by Chris Wilson.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=51265
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49838
Tested-by: Dave Airlie <airlied@gmail.com>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk> #855gm
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915/dvo-ch7xxx: fix get_hw_state

The boot-up state seems to be all-zeros, so it's safer to check for
the bits that need to be set when the dvo encoder is in the dpms on
state, than checking the bits we set when it's in the off state.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=55047
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: HSW CRW stability magic

This magic brings stability to HSW CRW machines.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm/i915: fix non-DP-D eDP backlight cleanup and module reload

Backlight is initialized for eDP, but cleaned up only for eDP on DP-D
port. This leaves behind a dangling backlight interface on module unload on
machines that have eDP connected to something other than DP-D, and breaks
the backlight interface for subsequent module reloads. Fix the cleanup, and
thus module reload on affected machines.

Reported-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Tested-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Merge tag 'disintegrate-sh-20121009' of git://git.infradead.org/users/dhowells/linux-headers into sh-latest

UAPI Disintegration 2012-10-09
sh: Wire up kcmp syscall.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
sh: Fix up more fallout from pointless ARM __iomem churn.

It was already pointed out how to fix these cases before the offending
patches were merged, but unsurprisingly, that didn't happen. As this
change is entirely superfluous to begin with, simply shut things up by
casting everything away.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>