linux-toradex.git/drivers/gpu/drm/mgag200, branch v4.4-rc6 Linux kernel for Apalis and Colibri modules drm/mgag200: fix kernel hang in cursor code. 2015-11-19T03:20:01+00:00 Wang, Rui Y rui.y.wang@intel.com 2015-11-18T15:00:53+00:00 f6619ef7508261be2ba3ded313ccc46ce670d0d3 The machine hang completely with the following message on the console: [ 487.777538] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 [ 487.777554] IP: [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30 [ 487.777557] PGD 42e9f7067 PUD 42f2fa067 PMD 0 [ 487.777560] Oops: 0002 [#1] SMP ... [ 487.777618] CPU: 21 PID: 3190 Comm: Xorg Tainted: G E 4.4.0-rc1-3-default+ #6 [ 487.777620] Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRHSXSD1.86B.0059.R00.1501081238 01/08/2015 [ 487.777621] task: ffff880853ae4680 ti: ffff8808696d4000 task.ti: ffff8808696d4000 [ 487.777625] RIP: 0010:[<ffffffff8158aaee>] [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30 [ 487.777627] RSP: 0018:ffff8808696d79c0 EFLAGS: 00010246 [ 487.777628] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 487.777629] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000060 [ 487.777630] RBP: ffff8808696d79e0 R08: 0000000000000000 R09: ffff88086924a780 [ 487.777631] R10: 000000000001bb40 R11: 0000000000003246 R12: 0000000000000000 [ 487.777632] R13: ffff880463a27360 R14: ffff88046ca50218 R15: 0000000000000080 [ 487.777634] FS: 00007f3f81c5a8c0(0000) GS:ffff88086f060000(0000) knlGS:0000000000000000 [ 487.777635] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 487.777636] CR2: 0000000000000060 CR3: 000000042e678000 CR4: 00000000001406e0 [ 487.777638] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 487.777639] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 487.777639] Stack: [ 487.777642] ffffffffa00eb5fa ffff8808696d7b60 ffff88086b87d800 0000000000000000 [ 487.777644] ffff8808696d7ac8 ffffffffa01694b6 ffff8808696d7ae8 ffffffff8109c8d5 [ 487.777647] ffff880469158740 ffff880463a27000 ffff88086b87d800 ffff88086b87d800 [ 487.777647] Call Trace: [ 487.777674] [<ffffffffa00eb5fa>] ? drm_gem_object_lookup+0x1a/0xa0 [drm] [ 487.777681] [<ffffffffa01694b6>] mga_crtc_cursor_set+0xc6/0xb60 [mgag200] [ 487.777691] [<ffffffff8109c8d5>] ? find_busiest_group+0x35/0x4a0 [ 487.777696] [<ffffffff81086294>] ? __might_sleep+0x44/0x80 [ 487.777699] [<ffffffff815888c2>] ? __ww_mutex_lock+0x22/0x9c [ 487.777722] [<ffffffffa0104f64>] ? drm_modeset_lock+0x34/0xf0 [drm] [ 487.777733] [<ffffffffa0148d9e>] restore_fbdev_mode+0xee/0x2a0 [drm_kms_helper] [ 487.777742] [<ffffffffa014afce>] drm_fb_helper_restore_fbdev_mode_unlocked+0x2e/0x70 [drm_kms_helper] [ 487.777748] [<ffffffffa014b037>] drm_fb_helper_set_par+0x27/0x50 [drm_kms_helper] [ 487.777752] [<ffffffff8134560c>] fb_set_var+0x18c/0x3f0 [ 487.777777] [<ffffffffa02a9b0a>] ? __ext4_handle_dirty_metadata+0x8a/0x210 [ext4] [ 487.777783] [<ffffffff8133cb97>] fbcon_blank+0x1b7/0x2b0 [ 487.777790] [<ffffffff813be2a3>] do_unblank_screen+0xb3/0x1c0 [ 487.777795] [<ffffffff813b5aba>] vt_ioctl+0x118a/0x1210 [ 487.777801] [<ffffffff813a8fe0>] tty_ioctl+0x3f0/0xc90 [ 487.777808] [<ffffffff81172018>] ? kzfree+0x28/0x30 [ 487.777813] [<ffffffff811e053f>] ? mntput+0x1f/0x30 [ 487.777817] [<ffffffff811d3f5d>] do_vfs_ioctl+0x30d/0x570 [ 487.777822] [<ffffffff8107ed3a>] ? task_work_run+0x8a/0xa0 [ 487.777825] [<ffffffff811d4234>] SyS_ioctl+0x74/0x80 [ 487.777829] [<ffffffff8158aeae>] entry_SYSCALL_64_fastpath+0x12/0x71 [ 487.777851] Code: 65 ff 0d ce 02 a8 7e 5d c3 ba 01 00 00 00 f0 0f b1 17 85 c0 75 e8 b0 01 5d c3 0f 1f 00 65 ff 05 b1 02 a8 7e 31 c0 ba 01 00 00 00 <f0> 0f b1 17 85 c0 75 01 c3 55 89 c6 48 89 e5 e8 4e f5 b1 ff 5d [ 487.777854] RIP [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30 [ 487.777855] RSP <ffff8808696d79c0> [ 487.777856] CR2: 0000000000000060 [ 487.777860] ---[ end trace 672a2cd555e0ebd3 ]--- The cursor code may be entered with file_priv == NULL && handle == NULL. The problem was introduced by: "bf89209 drm/mga200g: Hold a proper reference for cursor_set" which calls drm_gem_object_lookup(dev, file_priv...). Previously this wasn't a problem because we checked the handle. Move the check early in the function can fix the problem. Signed-off-by: Rui Wang <rui.y.wang@intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com> 
The machine hang completely with the following message on the console:

[  487.777538] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060
[  487.777554] IP: [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30
[  487.777557] PGD 42e9f7067 PUD 42f2fa067 PMD 0
[  487.777560] Oops: 0002 [#1] SMP
...
[  487.777618] CPU: 21 PID: 3190 Comm: Xorg Tainted: G            E   4.4.0-rc1-3-default+ #6
[  487.777620] Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRHSXSD1.86B.0059.R00.1501081238 01/08/2015
[  487.777621] task: ffff880853ae4680 ti: ffff8808696d4000 task.ti: ffff8808696d4000
[  487.777625] RIP: 0010:[<ffffffff8158aaee>]  [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30
[  487.777627] RSP: 0018:ffff8808696d79c0  EFLAGS: 00010246
[  487.777628] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  487.777629] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000060
[  487.777630] RBP: ffff8808696d79e0 R08: 0000000000000000 R09: ffff88086924a780
[  487.777631] R10: 000000000001bb40 R11: 0000000000003246 R12: 0000000000000000
[  487.777632] R13: ffff880463a27360 R14: ffff88046ca50218 R15: 0000000000000080
[  487.777634] FS:  00007f3f81c5a8c0(0000) GS:ffff88086f060000(0000) knlGS:0000000000000000
[  487.777635] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  487.777636] CR2: 0000000000000060 CR3: 000000042e678000 CR4: 00000000001406e0
[  487.777638] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  487.777639] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  487.777639] Stack:
[  487.777642]  ffffffffa00eb5fa ffff8808696d7b60 ffff88086b87d800 0000000000000000
[  487.777644]  ffff8808696d7ac8 ffffffffa01694b6 ffff8808696d7ae8 ffffffff8109c8d5
[  487.777647]  ffff880469158740 ffff880463a27000 ffff88086b87d800 ffff88086b87d800
[  487.777647] Call Trace:
[  487.777674]  [<ffffffffa00eb5fa>] ? drm_gem_object_lookup+0x1a/0xa0 [drm]
[  487.777681]  [<ffffffffa01694b6>] mga_crtc_cursor_set+0xc6/0xb60 [mgag200]
[  487.777691]  [<ffffffff8109c8d5>] ? find_busiest_group+0x35/0x4a0
[  487.777696]  [<ffffffff81086294>] ? __might_sleep+0x44/0x80
[  487.777699]  [<ffffffff815888c2>] ? __ww_mutex_lock+0x22/0x9c
[  487.777722]  [<ffffffffa0104f64>] ? drm_modeset_lock+0x34/0xf0 [drm]
[  487.777733]  [<ffffffffa0148d9e>] restore_fbdev_mode+0xee/0x2a0 [drm_kms_helper]
[  487.777742]  [<ffffffffa014afce>] drm_fb_helper_restore_fbdev_mode_unlocked+0x2e/0x70 [drm_kms_helper]
[  487.777748]  [<ffffffffa014b037>] drm_fb_helper_set_par+0x27/0x50 [drm_kms_helper]
[  487.777752]  [<ffffffff8134560c>] fb_set_var+0x18c/0x3f0
[  487.777777]  [<ffffffffa02a9b0a>] ? __ext4_handle_dirty_metadata+0x8a/0x210 [ext4]
[  487.777783]  [<ffffffff8133cb97>] fbcon_blank+0x1b7/0x2b0
[  487.777790]  [<ffffffff813be2a3>] do_unblank_screen+0xb3/0x1c0
[  487.777795]  [<ffffffff813b5aba>] vt_ioctl+0x118a/0x1210
[  487.777801]  [<ffffffff813a8fe0>] tty_ioctl+0x3f0/0xc90
[  487.777808]  [<ffffffff81172018>] ? kzfree+0x28/0x30
[  487.777813]  [<ffffffff811e053f>] ? mntput+0x1f/0x30
[  487.777817]  [<ffffffff811d3f5d>] do_vfs_ioctl+0x30d/0x570
[  487.777822]  [<ffffffff8107ed3a>] ? task_work_run+0x8a/0xa0
[  487.777825]  [<ffffffff811d4234>] SyS_ioctl+0x74/0x80
[  487.777829]  [<ffffffff8158aeae>] entry_SYSCALL_64_fastpath+0x12/0x71
[  487.777851] Code: 65 ff 0d ce 02 a8 7e 5d c3 ba 01 00 00 00 f0 0f b1 17 85 c0 75 e8 b0 01 5d c3 0f 1f 00 65 ff 05 b1 02 a8 7e 31 c0 ba 01 00 00 00 <f0> 0f b1 17 85 c0 75 01 c3 55 89 c6 48 89 e5 e8 4e f5 b1 ff 5d
[  487.777854] RIP  [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30
[  487.777855]  RSP <ffff8808696d79c0>
[  487.777856] CR2: 0000000000000060
[  487.777860] ---[ end trace 672a2cd555e0ebd3 ]---

The cursor code may be entered with file_priv == NULL && handle == NULL.
The problem was introduced by:

"bf89209 drm/mga200g: Hold a proper reference for cursor_set"

which calls drm_gem_object_lookup(dev, file_priv...). Previously this wasn't
a problem because we checked the handle. Move the check early in the function
can fix the problem.

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm/mgag200: Fix driver_load error handling 2015-09-23T22:10:44+00:00 Archit Taneja architt@codeaurora.org 2015-09-17T11:00:55+00:00 728f86607d47f7d2d24d61fd30852faa66ca5aa9 mgag200_driver_load's error path just calls the drm driver's driver_unload op. It isn't safe to call this because it doesn't handle things well if driver_load fails somewhere mid way. Replace the call to mgag200_driver_unload with a more finegrained error handling path. Link: http://lkml.kernel.org/r/55F6E68D.8070800@codeaurora.org Reported-by: Ingo Molnar <mingo@kernel.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dave Airlie <airlied@gmail.com> Cc: David Airlie <airlied@linux.ie> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel <dri-devel@lists.freedesktop.org> Signed-off-by: Archit Taneja <architt@codeaurora.org> Signed-off-by: Dave Airlie <airlied@redhat.com> 
mgag200_driver_load's error path just calls the drm driver's
driver_unload op. It isn't safe to call this because it doesn't handle
things well if driver_load fails somewhere mid way.

Replace the call to mgag200_driver_unload with a more finegrained
error handling path.

Link: http://lkml.kernel.org/r/55F6E68D.8070800@codeaurora.org
Reported-by: Ingo Molnar <mingo@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel <dri-devel@lists.freedesktop.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm/mgag200: Fix error handling paths in fbdev driver 2015-09-23T22:10:41+00:00 Archit Taneja architt@codeaurora.org 2015-09-17T11:00:54+00:00 aec9e12953e777f62acdab069656ebd9bcb6c9ba Set up error handling in mgag200_fbdev_init and mgag200fb_create such that they release the things they allocate, rather than relying on someone calling mga_fbdev_destroy. Based on a patch by Sudip Mukherjee <sudipm.mukherjee@gmail.com> Link: http://lkml.kernel.org/r/55F6E68D.8070800@codeaurora.org Reported-by: Ingo Molnar <mingo@kernel.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dave Airlie <airlied@gmail.com> Cc: David Airlie <airlied@linux.ie> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel <dri-devel@lists.freedesktop.org> Signed-off-by: Archit Taneja <architt@codeaurora.org> Signed-off-by: Dave Airlie <airlied@redhat.com> 
Set up error handling in mgag200_fbdev_init and mgag200fb_create such that
they release the things they allocate, rather than relying on someone
calling mga_fbdev_destroy.

Based on a patch by Sudip Mukherjee <sudipm.mukherjee@gmail.com>

Link: http://lkml.kernel.org/r/55F6E68D.8070800@codeaurora.org
Reported-by: Ingo Molnar <mingo@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel <dri-devel@lists.freedesktop.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm/mgag200: Add support for a new rev of G200e 2015-08-24T03:47:16+00:00 Mathieu Larouche mathieu.larouche@matrox.com 2015-08-21T13:24:13+00:00 e829d7ef9f17d7b84d4c3d110ecd4b7b2bcba865 - Added PLL algorithm for a new rev of G200e - Removed the bandwidth limitation for the new G200e Signed-off-by: Mathieu Larouche <mathieu.larouche@matrox.com> Signed-off-by: Dave Airlie <airlied@redhat.com> 
- Added PLL algorithm for a new rev of G200e
- Removed the bandwidth limitation for the new G200e

Signed-off-by: Mathieu Larouche <mathieu.larouche@matrox.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm/mgag200: Add support for a new G200eW3 chipset 2015-08-24T03:46:52+00:00 Mathieu Larouche mathieu.larouche@matrox.com 2015-08-21T13:24:05+00:00 6d857c18aefdec782ba1db578a390fbac5145107 - Added support for the new deviceID for G200eW3 - Added PLL algorithm for the G200eW3 - Added some initialization code for G200eW3 Signed-off-by: Mathieu Larouche <mathieu.larouche@matrox.com> Signed-off-by: Dave Airlie <airlied@redhat.com> 
- Added support for the new deviceID for G200eW3
- Added PLL algorithm for the G200eW3
- Added some initialization code for G200eW3

Signed-off-by: Mathieu Larouche <mathieu.larouche@matrox.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm/mga200g: Hold a proper reference for cursor_set 2015-08-10T11:37:20+00:00 Daniel Vetter daniel.vetter@ffwll.ch 2015-07-09T21:32:39+00:00 bf89209a6de37074e3ccdb7b40500798de750698 Looking up an obj, immediate dropping the acquired reference and then continuing to use it isn't how this is supposed to work. Fix this by holding a reference for the entire function. While at it stop grabbing dev->struct_mutex, it doesn't protect anything here. Reviewed-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> 
Looking up an obj, immediate dropping the acquired reference and then
continuing to use it isn't how this is supposed to work. Fix this by
holding a reference for the entire function.

While at it stop grabbing dev->struct_mutex, it doesn't protect
anything here.

Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
drm/mga200g: Don't grab dev->struct_mutex for in mmap offset ioctl 2015-08-10T11:37:12+00:00 Daniel Vetter daniel.vetter@ffwll.ch 2015-07-09T21:32:38+00:00 34c294f5a6c0dca7fb75ddc1be3ec8974b24455f Since David Herrmann's mmap vma manager rework we don't need to grab dev->struct_mutex any more to prevent races when looking up the mmap offset. Drop it and instead don't forget to use the unref_unlocked variant (since the drm core still cares). Reviewed-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> 
Since David Herrmann's mmap vma manager rework we don't need to grab
dev->struct_mutex any more to prevent races when looking up the mmap
offset. Drop it and instead don't forget to use the unref_unlocked
variant (since the drm core still cares).

Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
drm/mgag200: Use new drm_fb_helper functions 2015-08-06T12:13:04+00:00 Archit Taneja architt@codeaurora.org 2015-07-31T10:51:53+00:00 4f72a6eaedf71f3d7729086ca34703b3615f59d0 Use the newly created wrapper drm_fb_helper functions instead of calling core fbdev functions directly. They also simplify the fb_info creation. v3: - Don't touch remove_conflicting_framebuffers v2: - remove unused goto label 'out' Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@linux.ie> Cc: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Archit Taneja <architt@codeaurora.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> 
Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- remove unused goto label 'out'

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexander.deucher@amd.com>

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Merge tag 'topic/drm-misc-2015-07-23' of git://anongit.freedesktop.org/drm-intel into drm-next 2015-07-24T04:28:16+00:00 Dave Airlie airlied@redhat.com 2015-07-24T04:28:16+00:00 fa78ceab99e4481e17ab6b6a88257c1c7c23d55a Update drm-misc pull request since the first one didn't go in yet. Few atomic helper patches, rejecting some old dri1 crap for modern drivers and a few trivial things on top. * tag 'topic/drm-misc-2015-07-23' of git://anongit.freedesktop.org/drm-intel: drm/mgag200: remove unneeded variable drm/mgag200: remove unused variables drm/atomic: Only update crtc->x/y if it's part of the state, v2. drm/fb: drop panic handling drm: Fix warning with make xmldocs caused by drm_irq.c drm/gem: rip out drm vma accounting for gem mmaps drm/fourcc: Add formats R8, RG88, GR88 drm/atomic: Cleanup on error properly in the atomic ioctl. drm: Update plane->fb also for page_flip drm: remove redundant code form drm_ioc32.c drm: reset empty state in transitional helpers drm/crtc-helper: Fixup error handling in drm_helper_crtc_mode_set drm/atomic: Update old_fb after setting a property. drm: Remove useless blank line drm: Reject DRI1 hw lock ioctl functions for kms drivers drm: Convert drm_legacy_ctxbitmap_init to void return type drm: Turn off Legacy Context Functions 
Update drm-misc pull request since the first one didn't go in yet. Few
atomic helper patches, rejecting some old dri1 crap for modern drivers and
a few trivial things on top.

* tag 'topic/drm-misc-2015-07-23' of git://anongit.freedesktop.org/drm-intel:
  drm/mgag200: remove unneeded variable
  drm/mgag200: remove unused variables
  drm/atomic: Only update crtc->x/y if it's part of the state, v2.
  drm/fb: drop panic handling
  drm: Fix warning with make xmldocs caused by drm_irq.c
  drm/gem: rip out drm vma accounting for gem mmaps
  drm/fourcc: Add formats R8, RG88, GR88
  drm/atomic: Cleanup on error properly in the atomic ioctl.
  drm: Update plane->fb also for page_flip
  drm: remove redundant code form drm_ioc32.c
  drm: reset empty state in transitional helpers
  drm/crtc-helper: Fixup error handling in drm_helper_crtc_mode_set
  drm/atomic: Update old_fb after setting a property.
  drm: Remove useless blank line
  drm: Reject DRI1 hw lock ioctl functions for kms drivers
  drm: Convert drm_legacy_ctxbitmap_init to void return type
  drm: Turn off Legacy Context Functions
drm/mgag200: remove unneeded variable 2015-07-17T06:50:45+00:00 Sudip Mukherjee sudipm.mukherjee@gmail.com 2015-07-01T11:42:46+00:00 f9fe4b9b2ad4f2b801fdff3d634b07c9f9fc4327 ttm_bo_validate() returns 0 or error. So we can return the value directly and remove the variable 'ret'. Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> 
ttm_bo_validate() returns 0 or error. So we can return the value
directly and remove the variable 'ret'.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>