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Message-ID: <161843459482.46595.11409016331159748598@swboyd.mtv.corp.google.com>
Date: Wed, 14 Apr 2021 14:09:54 -0700
From: Stephen Boyd <swboyd@...omium.org>
To: Kuogee Hsieh <khsieh@...eaurora.org>, robdclark@...il.com,
sean@...rly.run
Cc: tanmay@...eaurora.org, abhinavk@...eaurora.org,
aravindh@...eaurora.org, khsieh@...eaurora.org, airlied@...ux.ie,
daniel@...ll.ch, linux-arm-msm@...r.kernel.org,
dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] drm/msm/dp: check main link status before start aux read
Quoting Kuogee Hsieh (2021-04-13 16:11:44)
> Make sure main link is in connection state before start aux
> read/write operation to avoid unnecessary long delay due to
> main link had been unplugged.
>
> Signed-off-by: Kuogee Hsieh <khsieh@...eaurora.org>
> ---
> drivers/gpu/drm/msm/dp/dp_aux.c | 5 +++++
> drivers/gpu/drm/msm/dp/dp_link.c | 20 +++++++++++++++-----
> 2 files changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
> index 7c22bfe..fae3806 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> @@ -343,6 +343,11 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
>
> mutex_lock(&aux->mutex);
>
> + if (!dp_catalog_link_is_connected(aux->catalog)) {
> + ret = -ETIMEDOUT;
> + goto unlock_exit;
> + }
I get a crash here sometimes when plugging and unplugging an apple HDMI
dongle during suspend/resume. I guess device power management
(dp_pm_suspend()) is happening in parallel with aux transfers from the
kthread. Why doesn't the aux communication start reporting NAKs once the
cable is disconnected?
[ 366.210058] hdmi-audio-codec hdmi-audio-codec.15.auto: calling platform_pm_suspend+0x0/0x60 @ 7175, parent: ae90000.displayport-controller
[ 366.222825] hdmi-audio-codec hdmi-audio-codec.15.auto: platform_pm_suspend+0x0/0x60 returned 0 after 1 usecs
[ 366.232939] msm-dp-display ae90000.displayport-controller: calling dp_pm_suspend+0x0/0x80 @ 7175, parent: ae00000.mdss
[ 366.244006] msm-dp-display ae90000.displayport-controller: dp_pm_suspend+0x0/0x80 returned 0 after 79 usecs
[ 366.254025] msm_dsi ae94000.dsi: calling pm_runtime_force_suspend+0x0/0xb4 @ 7175, parent: ae00000.mdss
[ 366.263669] msm_dsi ae94000.dsi: pm_runtime_force_suspend+0x0/0xb4 returned 0 after 0 usecs
[ 366.272290] panel-simple panel: calling platform_pm_suspend+0x0/0x60 @ 7175, parent: platform
[ 366.272501] ti_sn65dsi86 2-002d: calling pm_runtime_force_suspend+0x0/0xb4 @ 176, parent: i2c-2
[ 366.281055] panel-simple panel: platform_pm_suspend+0x0/0x60 returned 0 after 0 usecs
[ 366.281081] leds mmc1::: calling led_suspend+0x0/0x4c @ 7175, parent: 7c4000.sdhci
[ 366.290065] ti_sn65dsi86 2-002d: pm_runtime_force_suspend+0x0/0xb4 returned 0 after 0 usecs
[ 366.298046] leds mmc1::: led_suspend+0x0/0x4c returned 0 after 1 usecs
[ 366.302994] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP
[ 366.303006] Modules linked in: vhost_vsock vmw_vsock_virtio_transport_common vsock vhost rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE venus_enc hci_uart venus_dec btqca cros_ec_typec typec bluetooth qcom_spmi_adc5 snd_soc_sc7180 qcom_spmi_temp_alarm ecdh_generic qcom_spmi_adc_tm5 qcom_vadc_common snd_soc_qcom_common ecc snd_soc_rt5682_i2c snd_soc_rt5682 snd_soc_rl6231 venus_core v4l2_mem2mem snd_soc_lpass_sc7180 snd_soc_lpass_hdmi snd_soc_lpass_cpu snd_soc_lpass_platform snd_soc_max98357a fuse iio_trig_sysfs cros_ec_sensors cros_ec_sensors_ring cros_ec_lid_angle cros_ec_sensors_core industrialio_triggered_buffer kfifo_buf cros_ec_sensorhub lzo_rle lzo_compress zram ath10k_snoc ath10k_core ath mac80211 cfg80211 cdc_ether usbnet r8152 mii uvcvideo videobuf2_vmalloc joydev
[ 366.303211] CPU: 0 PID: 224 Comm: dp_hpd_handler Not tainted 5.4.109 #27
[ 366.303216] Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
[ 366.303225] pstate: 60c00009 (nZCv daif +PAN +UAO)
[ 366.303234] pc : dp_catalog_link_is_connected+0x20/0x34
[ 366.303244] lr : dp_aux_transfer+0x44/0x284
[ 366.303250] sp : ffffffc011bfbbe0
[ 366.303254] x29: ffffffc011bfbbe0 x28: aaaaaaaaaaaaaaaa
[ 366.303262] x27: 000000000000000c x26: ffffff896f8212bc
[ 366.303269] x25: 0000000000000001 x24: 0000000000000001
[ 366.303275] x23: 0000000000000020 x22: ffffff896ff82118
[ 366.303282] x21: ffffffc011bfbc50 x20: ffffff896ff82090
[ 366.303289] x19: ffffff896ffc3598 x18: 0000000000000000
[ 366.303295] x17: 0000000000000000 x16: 0000000000000001
[ 366.303303] x15: 0000000000000000 x14: 00000000000002ef
[ 366.303311] x13: 0000000000000400 x12: ffffffeb896ea060
[ 366.303317] x11: 0000000000000000 x10: 0000000000000000
[ 366.303324] x9 : ffffff896f061100 x8 : ffffffc010582204
[ 366.303331] x7 : 000000b2b5593519 x6 : 00000000003033ff
[ 366.303338] x5 : 0000000000000000 x4 : 0000000000000001
[ 366.303345] x3 : ffffff896ff432a1 x2 : 0000000000000000
[ 366.303352] x1 : 0000000000000119 x0 : ffffff896ffc3598
[ 366.303360] Call trace:
[ 366.303367] dp_catalog_link_is_connected+0x20/0x34
[ 366.303374] dp_aux_transfer+0x44/0x284
[ 366.303387] drm_dp_dpcd_access+0x8c/0x11c
[ 366.303393] drm_dp_dpcd_read+0x64/0x10c
[ 366.303399] dp_link_process_request+0x94/0xaf8
[ 366.303405] dp_display_usbpd_attention_cb+0x38/0x140
[ 366.303411] hpd_event_thread+0x3f0/0x48c
[ 366.303426] kthread+0x140/0x17c
[ 366.303439] ret_from_fork+0x10/0x18
[ 366.303458] Code: d503201f f85f0268 f9400508 91081108 (b9400108)
> +
> aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);
>
> /* Ignore address only message */
> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
> index be986da..d35b18e 100644
> --- a/drivers/gpu/drm/msm/dp/dp_link.c
> +++ b/drivers/gpu/drm/msm/dp/dp_link.c
> @@ -737,18 +737,25 @@ static int dp_link_parse_sink_count(struct dp_link *dp_link)
> return 0;
> }
>
> -static void dp_link_parse_sink_status_field(struct dp_link_private *link)
> +static int dp_link_parse_sink_status_field(struct dp_link_private *link)
> {
> int len = 0;
>
> link->prev_sink_count = link->dp_link.sink_count;
> - dp_link_parse_sink_count(&link->dp_link);
> + len = dp_link_parse_sink_count(&link->dp_link);
> + if (len < 0) {
> + DRM_ERROR("DP lparse sink count failed\n");
Is it 'lparse' on purpose?
> + return len;
> + }
>
> len = drm_dp_dpcd_read_link_status(link->aux,
> link->link_status);
> - if (len < DP_LINK_STATUS_SIZE)
> + if (len < DP_LINK_STATUS_SIZE) {
> DRM_ERROR("DP link status read failed\n");
> - dp_link_parse_request(link);
> + return len;
> + }
> +
> + return dp_link_parse_request(link);
> }
>
> /**
> @@ -1032,7 +1039,10 @@ int dp_link_process_request(struct dp_link *dp_link)
>
> dp_link_reset_data(link);
>
> - dp_link_parse_sink_status_field(link);
> + ret = dp_link_parse_sink_status_field(link);
> + if (ret) {
> + return ret;
> + }
>
> if (link->request.test_requested == DP_TEST_LINK_EDID_READ) {
> dp_link->sink_request |= DP_TEST_LINK_EDID_READ;
These are probably good fixes on their own given that
dp_link_parse_sink_count() can return an error and that was being
ignored.
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