Hi, On Thu, Jun 9, 2022 at 7:16 AM Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx> wrote: > > On 6/9/2022 2:17 AM, Rob Clark wrote: > > On Wed, Jun 8, 2022 at 12:36 PM Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx> wrote: > >> On 6/8/2022 3:00 AM, Rob Clark wrote: > >>> On Tue, Sep 28, 2021 at 7:52 AM Akhil P Oommen <akhilpo@xxxxxxxxxxxxxx> wrote: > >>>> On 9/27/2021 8:59 PM, Rob Clark wrote: > >>>>> From: Rob Clark <robdclark@xxxxxxxxxxxx> > >>>>> > >>>>> I've seen a few crashes like: > >>>>> > >>>>> Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP > >>>>> Modules linked in: snd_seq_dummy snd_seq snd_seq_device bridge stp llc tun nf_nat_tftp nf_conntrack_tftp nf_nat_ftp nf_conntrack_ftp esp6 ah6 ip6t_REJECT ip6t_ipv6header vhost_vsock vhost vmw_vsock_virtio_transport_common vsock rfcomm algif_hash algif_skcipher af_alg uinput veth xt_cgroup xt_MASQUERADE venus_enc venus_dec videobuf2_dma_contig qcom_spmi_adc5 qcom_spmi_adc_tm5 hci_uart qcom_vadc_common cros_ec_typec qcom_spmi_temp_alarm typec btqca snd_soc_rt5682_i2c snd_soc_rt5682 snd_soc_sc7180 bluetooth snd_soc_qcom_common snd_soc_rl6231 ecdh_generic ecc venus_core v4l2_mem2mem snd_soc_lpass_sc7180 snd_soc_lpass_hdmi snd_soc_lpass_cpu snd_soc_lpass_platform snd_soc_max98357a ip6table_nat fuse iio_trig_sysfs cros_ec_lid_angle cros_ec_sensors cros_ec_sensors_core industrialio_triggered_buffer kfifo_buf cros_ec_sensorhub lzo_rle ath10k_snoc lzo_compress ath10k_core ath zram mac80211 cfg80211 ax88179_178a usbnet mii uvcvideo videobuf2_vmalloc joydev > >>>>> CPU: 3 PID: 212 Comm: A618-worker Tainted: G W 5.4.139-16300-g88d8e1285982 #1 > >>>>> Hardware name: Google Pompom (rev1) with LTE (DT) > >>>>> pstate: 60c00009 (nZCv daif +PAN +UAO) > >>>>> pc : a6xx_gmu_set_oob+0x114/0x200 > >>>>> lr : a6xx_gmu_set_oob+0x10c/0x200 > >>>>> sp : ffffffc011b7bc20 > >>>>> x29: ffffffc011b7bc20 x28: ffffffdad27c5000 > >>>>> x27: 0000000000000001 x26: ffffffdad1521044 > >>>>> x25: ffffffbef7498338 x24: 0000000000000018 > >>>>> x23: 0000000000000002 x22: 0000000000014648 > >>>>> x21: 0000033732fe638b x20: 0000000080000000 > >>>>> x19: ffffffbef7433bc8 x18: 0000000040000000 > >>>>> x17: 000000243508d982 x16: 000000000000b67e > >>>>> x15: 00000000000090d4 x14: 0000000000000024 > >>>>> x13: 0000000000000024 x12: 0000000000017521 > >>>>> x11: 0000000000000b48 x10: 0000000000326a48 > >>>>> x9 : 1a130d33f6371600 x8 : ffffffc011e54648 > >>>>> x7 : 614948e00005003c x6 : ffffffbe3cd17e60 > >>>>> x5 : 0000000000000040 x4 : 0000000000000004 > >>>>> x3 : 0000000000000000 x2 : ffffffbef7488000 > >>>>> x1 : ffffffbef7488000 x0 : 0000000000000000 > >>>>> Call trace: > >>>>> a6xx_gmu_set_oob+0x114/0x200 > >>>>> a6xx_gmu_set_freq+0xe0/0x1fc > >>>>> msm_devfreq_target+0x80/0x13c > >>>>> msm_devfreq_idle+0x54/0x94 > >>>>> retire_submit+0x170/0x254 > >>>>> retire_submits+0xa4/0xdc > >>>>> retire_worker+0x1c/0x28 > >>>>> kthread_worker_fn+0xf4/0x1bc > >>>>> kthread+0x140/0x158 > >>>>> ret_from_fork+0x10/0x18 > >>>>> Code: 52800c81 9415bbe5 f9400a68 8b160108 (b9400108) > >>>>> ---[ end trace 16b871df2482cd61 ]--- > >>>>> Kernel panic - not syncing: Fatal exception > >>>>> SMP: stopping secondary CPUs > >>>>> Kernel Offset: 0x1ac1400000 from 0xffffffc010000000 > >>>>> PHYS_OFFSET: 0xffffffc280000000 > >>>>> CPU features: 0x88102e,2a80aa38 > >>>>> Memory Limit: none > >>>>> > >>>>> Which smells a lot like touching hw after power collapse. I'm not > >>>>> *entirely* sure how it could have taken 66ms (the autosuspend delay) > >>>>> before we get to a6xx_gmu_set_oob(), but to be safe we should move > >>>>> the pm_runtime_put_autosuspend() after msm_devfreq_idle(). > >>>> https://elixir.bootlin.com/linux/v5.15-rc1/source/drivers/gpu/drm/msm/adreno/a6xx_gmu.c#L132 > >>>> We have this check in the gmu freq set path which should avoid this > >>>> scenario. I might be a bit pedantic here, but I feel that the original > >>>> code is more accurate. We should immediately mark last busy and put > >>>> runtime_pm refcount. > >>> So, I've been doing some experiments, changing the _put_autosuspend() > >>> to _put_sync(), in the course of tracking down some remaining "GMU > >>> OOB" timeout type issues and related badness, and discovered things > >>> very quickly die with SError splats like below. Possibly the issue is > >>> that runpm has some race conditions, but I'm not sure we can trust > >>> pm_runtime_get_if_in_use() quite as much as one would like.. > >>> > >>> ----------- > >>> [ 33.225332] CPU: 0 PID: 216 Comm: A618-worker Tainted: G W > >>> 5.4.196 #7 > >>> [ 33.225337] Hardware name: Google Wormdingler rev1+ INX panel board (DT) > >>> [ 33.225343] pstate: 20c00009 (nzCv daif +PAN +UAO) > >>> [ 33.225353] pc : msm_readl+0x14/0x34 > >>> [ 33.225361] lr : a6xx_gpu_busy+0x40/0x80 > >>> [ 33.225365] sp : ffffffc011b93ad0 > >>> [ 33.225371] x29: ffffffc011b93ad0 x28: ffffffe77cba3000 > >>> [ 33.225377] x27: 0000000000000001 x26: ffffffe77bb4c4ac > >>> [ 33.225384] x25: ffffffa2f227dfa0 x24: ffffffa2f22aab28 > >>> [ 33.225390] x23: 0000000000000000 x22: ffffffa2f22bf020 > >>> [ 33.225397] x21: ffffffa2f22bf000 x20: ffffffc011b93b10 > >>> [ 33.225404] x19: ffffffc011bd4110 x18: 000000000000000e > >>> [ 33.225410] x17: 0000000000000004 x16: 000000000000000c > >>> [ 33.225416] x15: 000001be3a969450 x14: 0000000000000400 > >>> [ 33.225423] x13: 00000000000101d6 x12: 0000000034155555 > >>> [ 33.225429] x11: 0000000000000001 x10: 0000000000000000 > >>> [ 33.225436] x9 : 0000000100000000 x8 : ffffffc011bd4000 > >>> [ 33.225443] x7 : 0000000000000000 x6 : 0000000000000007 > >>> [ 33.225450] x5 : ffffffc01d8b38f0 x4 : 0000000000000000 > >>> [ 33.225457] x3 : 00000000ffffffff x2 : 0000000000000002 > >>> [ 33.225463] x1 : 0000000000000000 x0 : ffffffc011bd4110 > >>> [ 33.225471] Call trace: > >>> [ 33.225478] msm_readl+0x14/0x34 > >>> [ 33.225484] a6xx_gpu_busy+0x40/0x80 > >>> [ 33.225490] msm_devfreq_get_dev_status+0x70/0x1d0 > >>> [ 33.225500] devfreq_simple_ondemand_func+0x34/0x100 > >>> [ 33.225510] update_devfreq+0x50/0xe8 > >>> [ 33.225517] qos_notifier_call+0x2c/0x64 > >>> [ 33.225523] qos_max_notifier_call+0x1c/0x2c > >>> [ 33.225532] notifier_call_chain+0x58/0x98 > >>> [ 33.225539] __blocking_notifier_call_chain+0x74/0x84 > >>> [ 33.225545] blocking_notifier_call_chain+0x38/0x48 > >>> [ 33.225554] pm_qos_update_target+0xf8/0x19c > >>> [ 33.225560] freq_qos_apply+0x54/0x6c > >>> [ 33.225566] apply_constraint+0x60/0x104 > >>> [ 33.225572] __dev_pm_qos_update_request+0xb4/0x184 > >>> [ 33.225578] dev_pm_qos_update_request+0x38/0x58 > >>> [ 33.225584] msm_devfreq_idle_work+0x34/0x40 > >>> [ 33.225591] kthread_worker_fn+0x144/0x1c8 > >>> [ 33.225597] kthread+0x140/0x284 > >>> [ 33.225604] ret_from_fork+0x10/0x18 > >>> [ 33.225617] Code: f9000bf3 910003fd aa0003f3 d503201f (b9400260) > >>> [ 33.225623] ---[ end trace f6309767a42d0831 ]--- > >>> [ 33.236185] SMP: stopping secondary CPUs > >>> [ 33.236186] Kernel Offset: 0x276b600000 from 0xffffffc010000000 > >>> [ 33.236186] PHYS_OFFSET: 0xffffffdf80000000 > >>> [ 33.236187] CPU features: 0x088102e,2a80aa38 > >>> ----------- > >> Any chance we are racing with system suspend here? Because, when > >> "dev->power.disable_depth > 0", pm_runtime_get_if_in_use() returns > >> -EINVAL. Then I guess we should look for a positive return value from > >> pm_runtime_get_if_in_use() before proceeding. > > I think that is possible.. although I can still still SErrors in > > a6xx_gpu_busy() with: > > > > ---------- > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c > > b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c > > index 1ec90a9ca56c..61e1e33f355a 100644 > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c > > @@ -129,7 +129,7 @@ void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct > > dev_pm_opp *opp) > > * This can get called from devfreq while the hardware is idle. Don't > > * bring up the power if it isn't already active > > */ > > - if (pm_runtime_get_if_in_use(gmu->dev) == 0) > > + if (pm_runtime_get_if_in_use(gmu->dev) <= 0) > > return; > > > > if (!gmu->legacy) { > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > > b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > > index 95a6c3361a1e..b17a95f7b85c 100644 > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > > @@ -1456,7 +1456,7 @@ static u64 a6xx_gpu_busy(struct msm_gpu *gpu, > > unsigned long *out_sample_rate) > > *out_sample_rate = 19200000; > > > > /* Only read the gpu busy if the hardware is already active */ > > - if (pm_runtime_get_if_in_use(a6xx_gpu->gmu.dev) == 0) > > + if (pm_runtime_get_if_in_use(a6xx_gpu->gmu.dev) <= 0) > > return 0; > > > > busy_cycles = gmu_read64(&a6xx_gpu->gmu, > > ---------- > > > > So I don't think this completely explains it > > > > I am starting to think it might not be a bad idea to drain the gpu's > > kthread working in the suspend path > If it helps, draining kthread sounds like a better solution compared to > the current patch. Because msm_devfreq_idle() is queuing a work which > can still race with autosuspend + system-suspend under enough system > pressure. So I think I've tracked down the crashes that we were seeing and that they are fixed by: https://lore.kernel.org/r/20220609073317.1.Ie846c5352bc307ee4248d7cab998ab3016b85d06@changeid That being said, I'm still a fan of landing Rob's patch because it gets rid of the potential WARN_ON in adreno_runtime_suspend() and seems more correct. > -Akhil. > > > > BR, > > -R > > > >> -Akhil. > >>>> -Akhil. > >>>> > >>>>> Fixes: 9bc95570175a ("drm/msm: Devfreq tuning") > >>>>> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx> > >>>>> --- > >>>>> drivers/gpu/drm/msm/msm_gpu.c | 6 +++--- > >>>>> 1 file changed, 3 insertions(+), 3 deletions(-) > >>>>> > >>>>> diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c > >>>>> index d1a16642ecd5..2b2bbe7499e6 100644 > >>>>> --- a/drivers/gpu/drm/msm/msm_gpu.c > >>>>> +++ b/drivers/gpu/drm/msm/msm_gpu.c > >>>>> @@ -667,9 +667,6 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring, > >>>>> > >>>>> msm_submit_retire(submit); > >>>>> > >>>>> - pm_runtime_mark_last_busy(&gpu->pdev->dev); > >>>>> - pm_runtime_put_autosuspend(&gpu->pdev->dev); > >>>>> - > >>>>> spin_lock_irqsave(&ring->submit_lock, flags); > >>>>> list_del(&submit->node); > >>>>> spin_unlock_irqrestore(&ring->submit_lock, flags); > >>>>> @@ -683,6 +680,9 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring, > >>>>> mutex_unlock(&gpu->active_lock); > >>>>> > >>>>> msm_gem_submit_put(submit); > >>>>> + > >>>>> + pm_runtime_mark_last_busy(&gpu->pdev->dev); > >>>>> + pm_runtime_put_autosuspend(&gpu->pdev->dev); > >>>>> } > >>>>> > >>>>> static void retire_submits(struct msm_gpu *gpu) > >>>>> >
