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  1. 22 Oct, 2020 8 commits
  3. 21 Oct, 2020 13 commits
  5. 20 Oct, 2020 2 commits
  7. 19 Oct, 2020 11 commits
    • Chris Wilson's avatar
      drm/i915/gt: Wait for CSB entries on Tigerlake · 4a9bb58a
      Chris Wilson authored 
      On Tigerlake, we are seeing a repeat of commit d8f50531 ("drm/i915/icl:
Forcibly evict stale csb entries") where, presumably, due to a missing
Global Observation Point synchronisation, the write pointer of the CSB
ringbuffer is updated _prior_ to the contents of the ringbuffer. That is
we see the GPU report more context-switch entries for us to parse, but
those entries have not been written, leading us to process stale events,
and eventually report a hung GPU.

However, this effect appears to be much more severe than we previously
saw on Icelake (though it might be best if we try the same approach
there as well and measure), and Bruce suggested the good idea of resetting
the CSB entry after use so that we can detect when it has been updated by
the GPU. By instrumenting how long that may be, we can set a reliable
upper bound for how long we should wait for:

    513 late, avg of 61 retries (590 ns), max of 1061 retries (10099 ns)

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2045
References: d8f50531 ("drm/i915/icl: Forcibly evict stale csb entries")
References: HSDES#22011327657, HSDES#1508287568
Suggested-by: default avatarBruce Chang <yu.bruce.chang@intel.com>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Bruce Chang <yu.bruce.chang@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: stable@vger.kernel.org # v5.4
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200915134923.30088-2-chris@chris-wilson.co.uk
(cherry picked from commit 233c1ae3)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      4a9bb58a
    • Chris Wilson's avatar
      drm/i915/gt: Widen CSB pointer to u64 for the parsers · ca05277e
      Chris Wilson authored 
      A CSB entry is 64b, and it is simpler for us to treat it as an array of
64b entries than as an array of pairs of 32b entries.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200915134923.30088-1-chris@chris-wilson.co.uk
(cherry picked from commit f24a44e5)
(cherry picked from commit 3d4dbe0e0f0d04ebcea917b7279586817da8cf46)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      ca05277e
    • Chris Wilson's avatar
      drm/i915: Use the active reference on the vma while capturing · db9bc2d3
      Chris Wilson authored 
      During error capture, we need to take a reference to the vma from before
the reset in order to catpure the contents of the vma later. Currently
we are using both an active reference and a kref, but due to nature of
the i915_vma reference handling, that kref is on the vma->obj and not
the vma itself. This means the vma may be destroyed as soon as it is
idle, that is in between the i915_active_release(&vma->active) and the
i915_vma_put(vma):

<3> [197.866181] BUG: KASAN: use-after-free in intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<3> [197.866339] Read of size 8 at addr ffff8881258cb800 by task gem_exec_captur/1041
<3> [197.866467]
<4> [197.866512] CPU: 2 PID: 1041 Comm: gem_exec_captur Not tainted 5.9.0-g5e4234f97efba-kasan_200+ #1
<4> [197.866521] Hardware name: Intel Corp. Broxton P/Apollolake RVP1A, BIOS APLKRVPA.X64.0150.B11.1608081044 08/08/2016
<4> [197.866530] Call Trace:
<4> [197.866549]  dump_stack+0x99/0xd0
<4> [197.866760]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.866783]  print_address_description.constprop.8+0x3e/0x60
<4> [197.866797]  ? kmsg_dump_rewind_nolock+0xd4/0xd4
<4> [197.866819]  ? lockdep_hardirqs_off+0xd4/0x120
<4> [197.867037]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867249]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867270]  kasan_report.cold.10+0x1f/0x37
<4> [197.867492]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867710]  intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867949]  i915_gpu_coredump.part.29+0x150/0x7b0 [i915]
<4> [197.868186]  i915_capture_error_state+0x5e/0xc0 [i915]
<4> [197.868396]  intel_gt_handle_error+0x6eb/0xa20 [i915]
<4> [197.868624]  ? intel_gt_reset_global+0x370/0x370 [i915]
<4> [197.868644]  ? check_flags+0x50/0x50
<4> [197.868662]  ? __lock_acquire+0xd59/0x6b00
<4> [197.868678]  ? register_lock_class+0x1ad0/0x1ad0
<4> [197.868944]  i915_wedged_set+0xcf/0x1b0 [i915]
<4> [197.869147]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869371]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869398]  simple_attr_write+0x153/0x1c0
<4> [197.869428]  full_proxy_write+0xee/0x180
<4> [197.869442]  ? __sb_start_write+0x1f3/0x310
<4> [197.869465]  vfs_write+0x1a3/0x640
<4> [197.869492]  ksys_write+0xec/0x1c0
<4> [197.869507]  ? __ia32_sys_read+0xa0/0xa0
<4> [197.869525]  ? lockdep_hardirqs_on_prepare+0x32b/0x4e0
<4> [197.869541]  ? syscall_enter_from_user_mode+0x1c/0x50
<4> [197.869566]  do_syscall_64+0x33/0x80
<4> [197.869579]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<4> [197.869590] RIP: 0033:0x7fd8b7aee281
<4> [197.869604] Code: c3 0f 1f 84 00 00 00 00 00 48 8b 05 59 8d 20 00 c3 0f 1f 84 00 00 00 00 00 8b 05 8a d1 20 00 85 c0 75 16 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 57 f3 c3 0f 1f 44 00 00 41 54 55 49 89 d4 53
<4> [197.869613] RSP: 002b:00007ffea3b72008 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4> [197.869625] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd8b7aee281
<4> [197.869633] RDX: 0000000000000002 RSI: 00007fd8b81a82e7 RDI: 000000000000000d
<4> [197.869641] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000034
<4> [197.869650] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8b81a82e7
<4> [197.869658] R13: 000000000000000d R14: 0000000000000000 R15: 0000000000000000
<3> [197.869707]
<3> [197.869757] Allocated by task 1041:
<4> [197.869833]  kasan_save_stack+0x19/0x40
<4> [197.869843]  __kasan_kmalloc.constprop.5+0xc1/0xd0
<4> [197.869853]  kmem_cache_alloc+0x106/0x8e0
<4> [197.870059]  i915_vma_instance+0x212/0x1930 [i915]
<4> [197.870270]  eb_lookup_vmas+0xe06/0x1d10 [i915]
<4> [197.870475]  i915_gem_do_execbuffer+0x131d/0x4080 [i915]
<4> [197.870682]  i915_gem_execbuffer2_ioctl+0x103/0x5d0 [i915]
<4> [197.870701]  drm_ioctl_kernel+0x1d2/0x270
<4> [197.870710]  drm_ioctl+0x40d/0x85c
<4> [197.870721]  __x64_sys_ioctl+0x10d/0x170
<4> [197.870731]  do_syscall_64+0x33/0x80
<4> [197.870740]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<3> [197.870748]
<3> [197.870798] Freed by task 22:
<4> [197.870865]  kasan_save_stack+0x19/0x40
<4> [197.870875]  kasan_set_track+0x1c/0x30
<4> [197.870884]  kasan_set_free_info+0x1b/0x30
<4> [197.870894]  __kasan_slab_free+0x111/0x160
<4> [197.870903]  kmem_cache_free+0xcd/0x710
<4> [197.871109]  i915_vma_parked+0x618/0x800 [i915]
<4> [197.871307]  __gt_park+0xdb/0x1e0 [i915]
<4> [197.871501]  ____intel_wakeref_put_last+0xb1/0x190 [i915]
<4> [197.871516]  process_one_work+0x8dc/0x15d0
<4> [197.871525]  worker_thread+0x82/0xb30
<4> [197.871535]  kthread+0x36d/0x440
<4> [197.871545]  ret_from_fork+0x22/0x30
<3> [197.871553]
<3> [197.871602] The buggy address belongs to the object at ffff8881258cb740
 which belongs to the cache i915_vma of size 968

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2553
Fixes: 2850748e ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201016092527.29039-1-chris@chris-wilson.co.uk
(cherry picked from commit 178536b8)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      db9bc2d3
    • Chris Wilson's avatar
      drm/i915/gt: Undo forced context restores after trivial preemptions · 64402570
      Chris Wilson authored 
      We may try to preempt the currently executing request, only to find that
after unravelling all the dependencies that the original executing
context is still the earliest in the topological sort and re-submitted
back to HW (if we do detect some change in the ELSP that requires
re-submission). However, due to the way we check for wrap-around during
the unravelling, we mark any context that has been submitted just once
(i.e. with the rq->wa_tail set, but the ring->tail earlier) as
potentially wrapping and requiring a forced restore on resubmission.
This was expected to be not a problem, as it was anticipated that most
unwinding for preemption would result in a context switch and the few
that did not would be lost in the noise. It did not take long for
someone to find one particular workload where the cost of those extra
context restores was measurable.

However, since we know the wa_tail is of fixed size, and we know that a
request must be larger than the wa_tail itself, we can safely maintain
the check for request wrapping and check against a slightly future point
in the ring that includes an expected wa_tail. (That is if the
ring->tail is already set to rq->wa_tail, including another 8 bytes in
the check does not invalidate the incremental wrap detection.)

Fixes: 8ab3a381 ("drm/i915/gt: Incrementally check for rewinding")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Bruce Chang <yu.bruce.chang@intel.com>
Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.4+
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201002083425.4605-1-chris@chris-wilson.co.uk
(cherry picked from commit bb65548e)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      64402570
    • Chris Wilson's avatar
      drm/i915/gt: Delay execlist processing for tgl · 9b99e5ba
      Chris Wilson authored 
      When running gem_exec_nop, it floods the system with many requests (with
the goal of userspace submitting faster than the HW can process a single
empty batch). This causes the driver to continually resubmit new
requests onto the end of an active context, a flood of lite-restore
preemptions. If we time this just right, Tigerlake hangs.

Inserting a small delay between the processing of CS events and
submitting the next context, prevents the hang. Naturally it does not
occur with debugging enabled. The suspicion then is that this is related
to the issues with the CS event buffer, and inserting an mmio read of
the CS pointer status appears to be very successful in preventing the
hang. Other registers, or uncached reads, or plain mb, do not prevent
the hang, suggesting that register is key -- but that the hang can be
prevented by a simple udelay, suggests it is just a timing issue like
that encountered by commit 233c1ae3 ("drm/i915/gt: Wait for CSB
entries on Tigerlake"). Also note that the hang is not prevented by
applying CTX_DESC_FORCE_RESTORE, or by inserting a delay on the GPU
between requests.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Bruce Chang <yu.bruce.chang@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: stable@vger.kernel.org
Acked-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201015195023.32346-1-chris@chris-wilson.co.uk
(cherry picked from commit 6ca7217d)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      9b99e5ba
    • Chris Wilson's avatar
      drm/i915/gem: Support parsing of oversize batches · d5e87821
      Chris Wilson authored 
      Matthew Auld noted that on more recent systems (such as the parser for
gen9) we may have objects that are larger than expected by the GEM uAPI
(i.e. greater than u32). These objects would have incorrect implicit
batch lengths, causing the parser to reject them for being incomplete,
or worse.

Based on a patch by Matthew Auld.
Reported-by: default avatarMatthew Auld <matthew.auld@intel.com>
Fixes: 435e8fc0 ("drm/i915: Allow parsing of unsized batches")
Testcase: igt/gem_exec_params/larger-than-life-batch
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Cc: stable@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20201015115954.871-1-chris@chris-wilson.co.uk
(cherry picked from commit 57b2d834)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      d5e87821
    • Ville Syrjälä's avatar
      drm/i915: Mark ininitial fb obj as WT on eLLC machines to avoid rcu lockup during fbdev init · 1664ffee
      Ville Syrjälä authored 
      Currently we leave the cache_level of the initial fb obj
set to NONE. This means on eLLC machines the first pin_to_display()
will try to switch it to WT which requires a vma unbind+bind.
If that happens during the fbdev initialization rcu does not
seem operational which causes the unbind to get stuck. To
most appearances this looks like a dead machine on boot.

Avoid the unbind by already marking the object cache_level
as WT when creating it. We still do an excplicit ggtt pin
which will rewrite the PTEs anyway, so they will match whatever
cache level we set.

Cc: <stable@vger.kernel.org> # v5.7+
Suggested-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2381Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201007120329.17076-1-ville.syrjala@linux.intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20201015122138.30161-1-chris@chris-wilson.co.uk
(cherry picked from commit d46b60a2)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      1664ffee
    • Ayaz A Siddiqui's avatar
      drm/i915/gt: Initialize reserved and unspecified MOCS indices · 849c0fe9
      Ayaz A Siddiqui authored 
      In order to avoid functional breakage of mis-programmed applications that
have grown to depend on unused MOCS entries, we are programming
those entries to be equal to fully cached ("L3 + LLC") entry.

These reserved and unspecified entries should not be used as they may be
changed to less performant variants with better coherency in the future
if more entries are needed.

v2: As suggested by Lucas De Marchi to utilise __init_mocs_table for
programming default value, setting I915_MOCS_PTE index of tgl_mocs_table
with desired value.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Francisco Jerez <currojerez@riseup.net>
Cc: Mathew Alwin <alwin.mathew@intel.com>
Cc: Mcguire Russell W <russell.w.mcguire@intel.com>
Cc: Spruit Neil R <neil.r.spruit@intel.com>
Cc: Zhou Cheng <cheng.zhou@intel.com>
Cc: Benemelis Mike G <mike.g.benemelis@intel.com>
Signed-off-by: default avatarAyaz A Siddiqui <ayaz.siddiqui@intel.com>
Reviewed-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Acked-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200729102539.134731-2-ayaz.siddiqui@intel.com
Cc: stable@vger.kernel.org
(cherry picked from commit 4d8a5cfe)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      849c0fe9
    • Sean Paul's avatar
      drm/i915/dp: Tweak initial dpcd backlight.enabled value · 354842df
      Sean Paul authored 
      In commit 79946723 ("drm/i915: Assume 100% brightness when not in
DPCD control mode"), we fixed the brightness level when DPCD control was
not active to max brightness. This is as good as we can guess since most
backlights go on full when uncontrolled.

However in doing so we changed the semantics of the initial
'backlight.enabled' value. At least on Pixelbooks, they  were relying
on the brightness level in DP_EDP_BACKLIGHT_BRIGHTNESS_MSB to be 0 on
boot such that enabled would be false. This causes the device to be
enabled when the brightness is set. Without this, brightness control
doesn't work. So by changing brightness to max, we also flipped enabled
to be true on boot.

To fix this, make enabled a function of brightness and backlight control
mechanism.

Fixes: 79946723 ("drm/i915: Assume 100% brightness when not in DPCD control mode")
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Kevin Chowski <chowski@chromium.org>>
Signed-off-by: default avatarSean Paul <seanpaul@chromium.org>
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Signed-off-by: default avatarLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200918002845.32766-1-sean@poorly.run
(cherry picked from commit 4ade8f31)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      354842df
    • Peilin Ye's avatar
      Fonts: Support FONT_EXTRA_WORDS macros for font_6x8 · 272d7089
      Peilin Ye authored 
      Recently, in commit 6735b463 ("Fonts: Support FONT_EXTRA_WORDS macros
for built-in fonts"), we wrapped each of our built-in data buffers in a
`font_data` structure, in order to use the following macros on them, see
include/linux/font.h:

	#define REFCOUNT(fd)	(((int *)(fd))[-1])
	#define FNTSIZE(fd)	(((int *)(fd))[-2])
	#define FNTCHARCNT(fd)	(((int *)(fd))[-3])
	#define FNTSUM(fd)	(((int *)(fd))[-4])

	#define FONT_EXTRA_WORDS 4

Do the same thing to our new 6x8 font. For built-in fonts, currently we
only use FNTSIZE(). Since this is only a temporary solution for an
out-of-bounds issue in the framebuffer layer (see commit 5af08640
("fbcon: Fix global-out-of-bounds read in fbcon_get_font()")), all the
three other fields are intentionally set to zero in order to discourage
using these negative-indexing macros.
Signed-off-by: default avatarPeilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/926453876c92caac34cba8545716a491754d04d5.1603037079.git.yepeilin.cs@gmail.com
      272d7089
    • Peilin Ye's avatar
      docs: fb: Add font_6x8 to available built-in fonts · eda4a7bf
      Peilin Ye authored 
      Recently we added a new 6x8 font in commit e2028c8e ("lib/fonts: add
font 6x8 for OLED display"). Add its name to the "compiled-in fonts"
list.
Signed-off-by: default avatarPeilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201018205401.698242-1-yepeilin.cs@gmail.com
      eda4a7bf
  9. 18 Oct, 2020 3 commits
  11. 14 Oct, 2020 3 commits
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