Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> On Mon, Nov 28, 2016 at 02:02:33PM +0000, Tvrtko Ursulin wrote:
>>
>> On 25/11/2016 09:30, Chris Wilson wrote:
>> >Something I missed before sending off the partial series was that the
>> >non-scheduler guc reset path was broken (in the full series, this is
>> >pushed to the execlists reset handler). The issue is that after a reset,
>> >we have to refill the GuC workqueues, which we do by resubmitting the
>> >requests. However, if we already have submitted them, the fences within
>> >them have already been used and triggering them again is an error.
>> >Instead, just repopulate the guc workqueue.
>> >
>> >[ 115.858560] [IGT] gem_busy: starting subtest hang-render
>> >[ 135.839867] [drm] GPU HANG: ecode 9:0:0xe757fefe, in gem_busy [1716], reason: Hang on render ring, action: reset
>> >[ 135.839902] drm/i915: Resetting chip after gpu hang
>> >[ 135.839957] [drm] RC6 on
>> >[ 135.858351] ------------[ cut here ]------------
>> >[ 135.858357] WARNING: CPU: 2 PID: 45 at drivers/gpu/drm/i915/i915_sw_fence.c:108 i915_sw_fence_complete+0x25/0x30
>> >[ 135.858357] Modules linked in: rfcomm bnep binfmt_misc nls_iso8859_1 input_leds snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hda_core btusb btrtl snd_hwdep snd_pcm 8250_dw snd_seq_midi hid_lenovo snd_seq_midi_event snd_rawmidi iwlwifi x86_pkg_temp_thermal coretemp snd_seq crct10dif_pclmul snd_seq_device hci_uart snd_timer crc32_pclmul ghash_clmulni_intel idma64 aesni_intel virt_dma btbcm snd btqca aes_x86_64 btintel lrw cfg80211 bluetooth gf128mul glue_helper ablk_helper cryptd soundcore intel_lpss_pci intel_pch_thermal intel_lpss_acpi intel_lpss acpi_als mfd_core kfifo_buf acpi_pad industrialio autofs4 hid_plantronics usbhid dm_mirror dm_region_hash dm_log sdhci_pci ahci sdhci libahci i2c_hid hid
>> >[ 135.858389] CPU: 2 PID: 45 Comm: kworker/2:1 Tainted: G W 4.9.0-rc4+ #238
>> >[ 135.858389] Hardware name: /NUC6i3SYB, BIOS SYSKLi35.86A.0024.2015.1027.2142 10/27/2015
>> >[ 135.858392] Workqueue: events_long i915_hangcheck_elapsed
>> >[ 135.858394] ffffc900001bf9b8 ffffffff812bb238 0000000000000000 0000000000000000
>> >[ 135.858396] ffffc900001bf9f8 ffffffff8104f621 0000006c00000000 ffff8808296137f8
>> >[ 135.858398] 0000000000000a00 ffff8808457a0000 ffff880845764e60 ffff880845760000
>> >[ 135.858399] Call Trace:
>> >[ 135.858403] [<ffffffff812bb238>] dump_stack+0x4d/0x65
>> >[ 135.858405] [<ffffffff8104f621>] __warn+0xc1/0xe0
>> >[ 135.858406] [<ffffffff8104f748>] warn_slowpath_null+0x18/0x20
>> >[ 135.858408] [<ffffffff813f8c15>] i915_sw_fence_complete+0x25/0x30
>> >[ 135.858410] [<ffffffff813f8fad>] i915_sw_fence_commit+0xd/0x30
>> >[ 135.858412] [<ffffffff8142e591>] __i915_gem_request_submit+0xe1/0xf0
>> >[ 135.858413] [<ffffffff8142e5c8>] i915_gem_request_submit+0x28/0x40
>> >[ 135.858415] [<ffffffff814433e7>] i915_guc_submit+0x47/0x210
>> >[ 135.858417] [<ffffffff81443e98>] i915_guc_submission_enable+0x468/0x540
>> >[ 135.858419] [<ffffffff81442495>] intel_guc_setup+0x715/0x810
>> >[ 135.858421] [<ffffffff8142b6b4>] i915_gem_init_hw+0x114/0x2a0
>> >[ 135.858423] [<ffffffff813eeaa8>] i915_reset+0xe8/0x120
>> >[ 135.858424] [<ffffffff813f3937>] i915_reset_and_wakeup+0x157/0x180
>> >[ 135.858426] [<ffffffff813f79db>] i915_handle_error+0x1ab/0x230
>> >[ 135.858428] [<ffffffff812c760d>] ? scnprintf+0x4d/0x90
>> >[ 135.858430] [<ffffffff81435985>] i915_hangcheck_elapsed+0x275/0x3d0
>> >[ 135.858432] [<ffffffff810668cf>] process_one_work+0x12f/0x410
>> >[ 135.858433] [<ffffffff81066bf3>] worker_thread+0x43/0x4d0
>> >[ 135.858435] [<ffffffff81066bb0>] ? process_one_work+0x410/0x410
>> >[ 135.858436] [<ffffffff81066bb0>] ? process_one_work+0x410/0x410
>> >[ 135.858438] [<ffffffff8106bbb4>] kthread+0xd4/0xf0
>> >[ 135.858440] [<ffffffff8106bae0>] ? kthread_park+0x60/0x60
>> >
>> >v2: Only resubmit submitted requests
>> >v3: Don't forget the pending requests have reserved space.
>> >
>> >Fixes: d55ac5bf97c6 ("drm/i915: Defer transfer onto execution timeline to actual hw submission")
>> >Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>> >Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
>> >---
>> > drivers/gpu/drm/i915/i915_guc_submission.c | 37 ++++++++++++++++--------------
>> > 1 file changed, 20 insertions(+), 17 deletions(-)
>> >
>> >diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
>> >index 00b5fa871644..e12ff881d38d 100644
>> >--- a/drivers/gpu/drm/i915/i915_guc_submission.c
>> >+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
>> >@@ -602,12 +602,9 @@ static int guc_ring_doorbell(struct i915_guc_client *gc)
>> > }
>> >
>> > /**
>> >- * i915_guc_submit() - Submit commands through GuC
>> >+ * __i915_guc_submit() - Submit commands through GuC
>> > * @rq: request associated with the commands
>> > *
>> >- * Return: 0 on success, otherwise an errno.
>> >- * (Note: nonzero really shouldn't happen!)
>> >- *
>> > * The caller must have already called i915_guc_wq_reserve() above with
>> > * a result of 0 (success), guaranteeing that there is space in the work
>> > * queue for the new request, so enqueuing the item cannot fail.
>> >@@ -619,7 +616,7 @@ static int guc_ring_doorbell(struct i915_guc_client *gc)
>> > * The only error here arises if the doorbell hardware isn't functioning
>> > * as expected, which really shouln't happen.
>> > */
>> >-static void i915_guc_submit(struct drm_i915_gem_request *rq)
>> >+static void __i915_guc_submit(struct drm_i915_gem_request *rq)
>> > {
>> > struct drm_i915_private *dev_priv = rq->i915;
>> > struct intel_engine_cs *engine = rq->engine;
>> >@@ -628,17 +625,6 @@ static void i915_guc_submit(struct drm_i915_gem_request *rq)
>> > struct i915_guc_client *client = guc->execbuf_client;
>> > int b_ret;
>> >
>> >- /* We keep the previous context alive until we retire the following
>> >- * request. This ensures that any the context object is still pinned
>> >- * for any residual writes the HW makes into it on the context switch
>> >- * into the next object following the breadcrumb. Otherwise, we may
>> >- * retire the context too early.
>> >- */
>> >- rq->previous_context = engine->last_context;
>> >- engine->last_context = rq->ctx;
>> >-
>> >- i915_gem_request_submit(rq);
>> >-
>> > spin_lock(&client->wq_lock);
>> > guc_wq_item_append(client, rq);
>> >
>> >@@ -658,6 +644,23 @@ static void i915_guc_submit(struct drm_i915_gem_request *rq)
>> > spin_unlock(&client->wq_lock);
>> > }
>> >
>> >+static void i915_guc_submit(struct drm_i915_gem_request *rq)
>> >+{
>> >+ struct intel_engine_cs *engine = rq->engine;
>> >+
>> >+ /* We keep the previous context alive until we retire the following
>> >+ * request. This ensures that any the context object is still pinned
>> >+ * for any residual writes the HW makes into it on the context switch
>> >+ * into the next object following the breadcrumb. Otherwise, we may
>> >+ * retire the context too early.
>> >+ */
>> >+ rq->previous_context = engine->last_context;
>> >+ engine->last_context = rq->ctx;
>> >+
>> >+ i915_gem_request_submit(rq);
>> >+ __i915_guc_submit(rq);
>> >+}
>> >+
>> > /*
>> > * Everything below here is concerned with setup & teardown, and is
>> > * therefore not part of the somewhat time-critical batch-submission
>> >@@ -1556,7 +1559,7 @@ int i915_guc_submission_enable(struct drm_i915_private *dev_priv)
>> > /* Replay the current set of previously submitted requests */
>> > list_for_each_entry(rq, &engine->timeline->requests, link) {
>> > client->wq_rsvd += sizeof(struct guc_wq_item);
>> >- i915_guc_submit(rq);
>> >+ __i915_guc_submit(rq);
>> > }
>> > }
>> >
>> >
>>
>> The only thing bothering me here is how this interacts with the
>> common, or "execlist" part of the reset.
>
> Also applies to ringbuffer (some parts at least).
>
>> Copying Mika in hope he can help here. :)
>>
>> I see that i915_gem_reset_engine runs before this GuC wq refill and
>> does some magic with the requests on the engine->timeline->requests
>> lists.
>>
>> Would it be possible to somehow better integrate the two things?
>
> I thought they were nicely separated. The common work to disable the
> guilty context is handled by the core reset function. The specific work
> required to restart and replay the requests handled by the different
> backends.
>
> i915_gem_reset_engine: is for disabling the guilty context
> engine->reset: updates the context / ring for restarting past a hung
> batch (if required)
> engine->init: starts the engine, processing the pending requests if any
>
> engine->reset is a bad name, since we have per-engine resets as well,
> but I haven't a better verb yet for handling the request bumping after
> a
How about
engine->setup(request *) to replace ->reset
and engine->start() to replace ->init()?
-Mika
> reset.
> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
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