[REGRESSION][BISECTED] No display on rk3399-gru-kevin
Damon Ding
damon.ding at rock-chips.com
Sun Jun 21 19:02:23 PDT 2026
Hi Vicente,
On 6/19/2026 7:51 AM, Vicente Bergas wrote:
> On Thu, Jun 18, 2026 at 5:49 AM Damon Ding <damon.ding at rock-chips.com> wrote:
>>
>> Hi Vicente,
>>
>> On 6/18/2026 7:15 AM, Vicente Bergas wrote:
>>> On Wed, Jun 17, 2026 at 10:45 AM Heiko Stübner <heiko at sntech.de> wrote:
>>>>
>>>> Hi Vicente,
>>>>
>>>> Am Mittwoch, 17. Juni 2026, 01:05:27 Mitteleuropäische Sommerzeit schrieb Vicente Bergas:
>>>>> Hello,
>>>>> there are two issues that result on a black screen on the rk3399-gru-kevin.
>>>>>
>>>>> The first one is due to:
>>>>> c8079f83e0bf312645050c17d9c87deb707369c1
>>>>> gpio: rockchip: convert to dynamic GPIO base allocation
>>>>
>>>> can you check that your kernel contains
>>>> "gpio: rockchip: Fix GPIO regression after conversion to dynamic base allocation"
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=5cd9c6d332f46d1de8b68117fe2a3f1b08ee80ff
>>>
>>> Yes, that commit is in v7.1 and it indeed fixes the gpio issue.
>>> I tested reverting c8079f83 alone and reverting all three.
>>> Now i've tested only reverting 51eb548a and d84b087c, and it works.
>>> The thing is both bugs coexisted at some point and
>>> git bisect finds them in order.
>>>
>>>>> Reverting this does not fix the problem as there is a second one:
>>>>> 51eb548ade20158b4f4f8693a95b1f31a2480e8e
>>>>> drm/bridge: analogix_dp: Apply DP helper API drm_dp_channel_eq_ok()
>>>>>
>>>>> That second one depends on:
>>>>> d84b087c7662dd65cd51b228219987c31b1cee02
>>>>> drm/bridge: analogix_dp: Apply DP helper APIs to get adjusted voltages
>>>>> and pre-emphasises
>>>>>
>>>>> Reverting all three commits from v7.1 make the display work again.
>>>>>
>>>>> Please, can this be resolved?
>>>>
>>>> and as Damon wrote, please provide logs, so we can see the actual problem
>>>
>>> It is quite difficult to read the logs from a black screen...
>>> Jokes apart, here they are:
>>>
>>> Relevant log entries:
>>> <6>[ 0.043668] /dp at fec00000: Fixed dependency cycle(s) with /vop at ff8f0000
>>> <6>[ 0.043735] /vop at ff8f0000: Fixed dependency cycle(s) with /dp at fec00000
>>> <6>[ 0.044192] /dp at fec00000: Fixed dependency cycle(s) with /vop at ff900000
>>> <6>[ 0.044250] /vop at ff900000: Fixed dependency cycle(s) with /dp at fec00000
>>> <6>[ 0.045064] /vop at ff900000: Fixed dependency cycle(s) with /dp at ff970000
>>> <6>[ 0.045122] /vop at ff8f0000: Fixed dependency cycle(s) with /dp at ff970000
>>> <6>[ 0.045194] /dp at ff970000: Fixed dependency cycle(s) with /vop at ff8f0000
>>> <6>[ 0.045264] /dp at ff970000: Fixed dependency cycle(s) with /vop at ff900000
>>> <6>[ 0.058590] /dp at ff970000: Fixed dependency cycle(s) with /edp-panel
>>> <6>[ 0.058733] /edp-panel: Fixed dependency cycle(s) with /dp at ff970000
>>> <6>[ 0.101266] platform ff8f0000.vop: Adding to iommu group 2
>>> <6>[ 0.102073] platform ff900000.vop: Adding to iommu group 3
>>> <3>[ 0.105258] rockchip-dp ff970000.dp: no DP phy configured
>>> <3>[ 0.308638] rockchip-dp ff970000.dp: no DP phy configured
>>> <6>[ 0.310104] panfrost ff9a0000.gpu: clock rate = 500000000
>>> <6>[ 0.311210] panfrost ff9a0000.gpu: mali-t860 id 0x860 major 0x2
>>> minor 0x0 status 0x0
>>> <6>[ 0.311223] panfrost ff9a0000.gpu: features: 00000000,00000407,
>>> issues: 00000000,24040400
>>> <6>[ 0.311231] panfrost ff9a0000.gpu: Features: L2:0x07120206
>>> Shader:0x00000000 Tiler:0x00000809 Mem:0x1 MMU:0x00002830 AS:0xff
>>> JS:0x7
>>> <6>[ 0.311239] panfrost ff9a0000.gpu: shader_present=0xf l2_present=0x1
>>> <6>[ 0.312664] [drm] Initialized panfrost 1.6.0 for ff9a0000.gpu on minor 0
>>> <3>[ 0.624232] rockchip-dp ff970000.dp: no DP phy configured
>>> <3>[ 0.639611] rockchip-dp ff970000.dp: no DP phy configured
>>> <6>[ 0.641512] rockchip-drm display-subsystem: bound ff900000.vop
>>> (ops 0xffff800080c9a3c8)
>>> <6>[ 0.642646] rockchip-drm display-subsystem: bound ff8f0000.vop
>>> (ops 0xffff800080c9a3c8)
>>> <4>[ 0.643198] [drm] Missing drm_bridge_add() before attach
>>> <6>[ 0.643238] rockchip-drm display-subsystem: bound ff970000.dp
>>> (ops 0xffff800080c9e840)
>>> <6>[ 0.644029] rockchip-drm display-subsystem: bound fec00000.dp
>>> (ops 0xffff800080c9f0c8)
>>> <6>[ 0.644102] cdn-dp fec00000.dp: [drm:cdn_dp_pd_event_work] Not
>>> connected; disabling cdn
>>> <6>[ 0.644837] [drm] Initialized rockchip 1.0.0 for
>>> display-subsystem on minor 1
>>> <4>[ 0.786773] panel-edp edp-panel: Skipping disable of already
>>> disabled panel
>>> <3>[ 0.796517] rockchip-dp ff970000.dp: EQ Max loop
>>> <3>[ 0.797745] rockchip-dp ff970000.dp: LT EQ failed!
>>> <3>[ 0.797757] rockchip-dp ff970000.dp: eDP link training failed (-5)
>>> <3>[ 0.797770] rockchip-dp ff970000.dp: unable to do link train, ret=-5
>>> <3>[ 0.797783] [drm:analogix_dp_bridge_atomic_enable] *ERROR* dp
>>> commit error, ret = -5
>>> <3>[ 0.797823] rockchip-dp ff970000.dp: failed to set bridge, retry: 0
>>> <4>[ 0.797937] panel-edp edp-panel: Skipping disable of already
>>> disabled panel
>>> <3>[ 0.808097] rockchip-dp ff970000.dp: EQ Max loop
>>> <3>[ 0.809284] rockchip-dp ff970000.dp: LT EQ failed!
>>> <3>[ 0.809299] rockchip-dp ff970000.dp: eDP link training failed (-5)
>>> <3>[ 0.809314] rockchip-dp ff970000.dp: unable to do link train, ret=-5
>>> <3>[ 0.809326] [drm:analogix_dp_bridge_atomic_enable] *ERROR* dp
>>> commit error, ret = -5
>>> <3>[ 0.809353] rockchip-dp ff970000.dp: failed to set bridge, retry: 1
>>> <4>[ 0.809463] panel-edp edp-panel: Skipping disable of already
>>> disabled panel
>>> <3>[ 0.819481] rockchip-dp ff970000.dp: EQ Max loop
>>> <3>[ 0.820745] rockchip-dp ff970000.dp: LT EQ failed!
>>> <3>[ 0.820758] rockchip-dp ff970000.dp: eDP link training failed (-5)
>>> <3>[ 0.820772] rockchip-dp ff970000.dp: unable to do link train, ret=-5
>>> <3>[ 0.820781] [drm:analogix_dp_bridge_atomic_enable] *ERROR* dp
>>> commit error, ret = -5
>>> <3>[ 0.820806] rockchip-dp ff970000.dp: failed to set bridge, retry: 2
>>> <4>[ 0.820919] panel-edp edp-panel: Skipping disable of already
>>> disabled panel
>>> <3>[ 0.831075] rockchip-dp ff970000.dp: EQ Max loop
>>> <3>[ 0.832336] rockchip-dp ff970000.dp: LT EQ failed!
>>> <3>[ 0.832346] rockchip-dp ff970000.dp: eDP link training failed (-5)
>>> <3>[ 0.832356] rockchip-dp ff970000.dp: unable to do link train, ret=-5
>>> <3>[ 0.832367] [drm:analogix_dp_bridge_atomic_enable] *ERROR* dp
>>> commit error, ret = -5
>>> <3>[ 0.832388] rockchip-dp ff970000.dp: failed to set bridge, retry: 3
>>> <4>[ 0.832496] panel-edp edp-panel: Skipping disable of already
>>> disabled panel
>>> <3>[ 0.842613] rockchip-dp ff970000.dp: EQ Max loop
>>> <3>[ 0.843754] rockchip-dp ff970000.dp: LT EQ failed!
>>> <3>[ 0.843765] rockchip-dp ff970000.dp: eDP link training failed (-5)
>>> <3>[ 0.843778] rockchip-dp ff970000.dp: unable to do link train, ret=-5
>>> <3>[ 0.843791] [drm:analogix_dp_bridge_atomic_enable] *ERROR* dp
>>> commit error, ret = -5
>>> <3>[ 0.843815] rockchip-dp ff970000.dp: failed to set bridge, retry: 4
>>> <3>[ 0.843857] rockchip-dp ff970000.dp: too many times retry set
>>> bridge, give it up
>>> <6>[ 0.854625] Console: switching to colour frame buffer device 300x100
>>> <6>[ 0.887526] rockchip-drm display-subsystem: [drm] fb0:
>>> rockchipdrmfb frame buffer device
>>>
>>>
>>
>> I have tested RK3399 IND EVB locally based on kernel v7.1, and eDP
>> training completes successfully with normal display output with patch
>> 0001-arm64-dts-rockchip-Enable-eDP-display-for-RK3399-IND.patch applied.
>>
>> From your logs, the failure occurs during the EQ stage of eDP training.
>> Please apply the additional patch
>> 0002-drm-bridge-analogix_dp-Read-CR-EQ-delay-from-DPCD-in.patch without
>> reverting the two commits mentioned above (51eb548a and d84b087c), then
>> retest to check if the issue gets improved.
>> (BTW: This is a test-only temporary patch with minor style flaws, but
>> the patch needs upstreaming. I'll rework and send a formal version soon.)
>
> Hi Damon,
> applying patch 0001 and 0002 does not fix the issue.
> The logs are mostly the same.
>
>> If the problem persists, try adding a small delay at the location
>> mentioned below for further verification:
>
> applying the extra delay results are the same, just small noise in the
> dmesg timestamps.
>
> Besides this, i've done another test:
> i have reverted 51eb548a while keeping d84b087c, which i had to rebase.
> The result is again the same: black screen and the logs are again equivalent.
> That proves that both patches 51eb548a and d84b087c each introduce a regression.
>
Thanks a lot for all these thorough tests, your results give me much
clearer clues.
I suspect the root cause is not the EQ training delay, but incorrect PE
(pre-emphasis) and VS (voltage swing) register configuration.
Please do not revert any of the two commits mentioned above. Instead,
apply the following patch which may properly resolve the black screen
issue you are seeing:
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index a5dc645d7005..30ad952c5c12 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -306,7 +306,9 @@ static void
analogix_dp_get_adjust_training_lane(struct analogix_dp_device *dp,
lane_count = dp->link_train.lane_count;
for (lane = 0; lane < lane_count; lane++) {
voltage_swing =
drm_dp_get_adjust_request_voltage(link_status, lane);
+ voltage_swing >>= DP_TRAIN_VOLTAGE_SWING_SHIFT;
pre_emphasis =
drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
+ pre_emphasis >>= DP_TRAIN_PRE_EMPHASIS_SHIFT;
training_lane = DPCD_VOLTAGE_SWING_SET(voltage_swing) |
DPCD_PRE_EMPHASIS_SET(pre_emphasis);
@@ -352,7 +354,9 @@ static int analogix_dp_process_clock_recovery(struct
analogix_dp_device *dp)
for (lane = 0; lane < lane_count; lane++) {
training_lane = analogix_dp_get_lane_link_training(dp,
lane);
voltage_swing =
drm_dp_get_adjust_request_voltage(link_status, lane);
+ voltage_swing >>= DP_TRAIN_VOLTAGE_SWING_SHIFT;
pre_emphasis =
drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
+ pre_emphasis >>= DP_TRAIN_PRE_EMPHASIS_SHIFT;
if (DPCD_VOLTAGE_SWING_GET(training_lane) ==
voltage_swing &&
DPCD_PRE_EMPHASIS_GET(training_lane) == pre_emphasis)
Without this fix, there is no obvious error when pre-emphasis equals 0,
but wrong register values will be programmed once PE is non-zero.
Best regards,
Damon
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