[REGRESSION][BISECTED] No display on rk3399-gru-kevin

Thu Jun 18 16:51:38 PDT 2026

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.

Regards,
  Vicente.

> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index a5dc645d7005..6dac3974acb5 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -401,6 +401,8 @@ static int
> analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
>
>          analogix_dp_get_adjust_training_lane(dp, link_status);
>
> +       usleep_range(5000, 6000);
> +
>          if (drm_dp_channel_eq_ok(link_status, lane_count)) {
>                  /* traing pattern Set to Normal */
>                  retval = analogix_dp_training_pattern_dis(dp);
> (Note: This delay is only for testing purpose)
>
> Best regards,
> Damon