Re: [PATCH v10 0/17] Add Analogix Core Display Port Driver

[Yakir Yang <ykk@rock-chips.com>]

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Hi Heiko,

Thanks a lot for great debugging.

On 12/08/2015 11:33 PM, Heiko Stübner wrote:
> Hi Yakir,
>
> Am Montag, 7. Dezember 2015, 14:37:19 schrieb Yakir Yang:
>>     The Samsung Exynos eDP controller and Rockchip RK3288 eDP controller
>> share the same IP, so a lot of parts can be re-used. I split the common
>> code into bridge directory, then rk3288 and exynos only need to keep
>> some platform code. Cause I can't find the exact IP name of exynos dp
>> controller, so I decide to name dp core driver with "analogix" which I
>> find in rk3288 eDP TRM
> [...]
>
>> Changes in v10:
>> - Correct the ROCKCHIP_ANALOGIX_DP indentation in Kconfig to tabs here
>> (Heiko) - Fix the wrong macro value of
>> GRF_EDP_REF_CLK_SEL_INTER_HIWORD_MASK BIT(4) -> BIT(20)
>> - Remove the surplus "plat_data" check. (Heiko)
>> -       switch (dp->plat_data && dp->plat_data->dev_type) {
>> +       switch (dp->plat_data->dev_type) {
>> - Revert parts of Gustavo Padovan's changes in commit:
>> 	drm/exynos: do not start enabling DP at bind() phase
>>    Add dp phy poweron function in bind time.
> The hotplug issue is still present, but I think I found the cause. When
> the first detect call happens, the display simply is still off. I just did
> some very basic tracing [0] and it seems the display simply is not enabled
> when it is supposed to get detected.

Aha, thanks, make a lot of sense.

> And it seems injecting a drm_panel_prepare early for _testing_ [1] really
> did make the hotplug work on both my jerry and minnie.
>
> So I guess we should somehow make sure the panel is actually powered when
> detection is running. Although I'm not sure yet, how that should look like.

Agree, panel should be powered up before DP controller start to detect 
hotplug signal.

> Intuition suggests, making drm_panel calls nestable (similar to
> clk_prepare/unprepare, etc) and simply wrapping the detection code
> in a prepare-unprepare calls, but I'm not sure if Thierry might have other
> ideas ;-)

Due to the panel power status would influence the hotplug status, so I 
think we don't
need to unprepared the panel unless in driver enter into suspend time. 
Things I want:

1. Prepared the panel in driver *bind time*
2. Enable the panel in driver *bridge->enable time*
3. Disable the panel in driver *bridge->disable time*
4. Unprepared the panel in driver*suspend time *
5. Re-prepared the panel in driver *resume time*

> Also my "log" below suggests some sort of mismatch between
> prepare/unprepare calls, as there are a lot more of the prepare-side.

Yes, it's a typo too. I shouldn't place the panel->prepare in 
connector->get_modes,
cause userspace would try to call get_modes once it receive the hotplug 
event, so
there wouldn't have a match between panel prepare/unprepare.

Previously, I just want to ensure that panel should be power-up when 
driver try to
read the EDID from panel, so for now must remove the prepare from 
get_modes time  :)

> And the locking issue also seems to be still there [2].

Hmm, I haven't meet this dead lock on my chromebook (ChromeOS + 4.4-rc3 
Kernel)

After look at the dead lock trace, I guess this dead lock would happened 
when hotplug
event happened in bridge->disable time, not sure.  Would try to find 
more in trace log
and try to reproduce this.


- Yakir

>
> Heiko
>
>
> [0]
> [    2.797383] analogix_dp_reset
> [    2.800709] analogix_dp_init_hpd
> [    2.803960] analogix_dp_init_video
> [    2.807653] rockchip-drm display-subsystem: bound ff970000.dp (ops rockchip_dp_component_ops)
> [    2.817176] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> [    2.823799] [drm] No driver support for vblank timestamp query.
> [    2.829947] analogix_dp_detect
> [    2.833015] analogix_dp_get_plug_in_status: hpd status 0
> ...
> [    2.893425] analogix_dp_get_plug_in_status: hpd status 0
> [    2.893456] rockchip-dp ff970000.dp: failed to get hpd plug status, try to force hpd
> [    2.893458] analogix_dp_force_hpd
> [    2.893464] analogix_dp_get_plug_in_status: hpd status 112
> [    2.893470] panel_simple_prepare
> [    2.952183] rockchip-dp ff970000.dp: EDID data does not include any extensions.
> [    2.961727] panel_simple_get_modes
> [    3.432154] analogix_dp_detect
> [    3.432158] analogix_dp_get_plug_in_status: hpd status 120
> [    3.432160] panel_simple_prepare
> [    3.433731] rockchip-dp ff970000.dp: EDID data does not include any extensions.
> [    3.443268] panel_simple_get_modes
> [    3.444668] panel_simple_prepare
> [    3.444755] analogix_dp_reset
> [    3.445078] analogix_dp_init_hpd
> [    3.445096] panel_simple_disable
> [    3.455349] analogix_dp_init_video
> [    3.558323] rockchip-dp ff970000.dp: Timeout of video streamclk ok
> [    3.558326] rockchip-dp ff970000.dp: unable to config video
> [    3.558328] panel_simple_enable
> [    3.573915] analogix_dp_detect
> [    3.573919] analogix_dp_get_plug_in_status: hpd status 72
> [    3.573921] panel_simple_prepare
>
>
> [1]
> diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> index 3990951..0c2dca5 100644
> --- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> +++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> @@ -399,6 +399,8 @@ static int rockchip_dp_probe(struct platform_device *pdev)
>   
>          dp->plat_data.panel = panel;
>   
> +drm_panel_prepare(dp->plat_data.panel);
> +
>          /*
>           * We just use the drvdata until driver run into component
>           * add function, and then we would set drvdata to null, so
>
>
> [2]
> [   11.971277] panel_simple_get_modes
> [  OK  ] Started LSB: X display manager for KDE.
> [  OK  ] Started LSB: Speech Dispatcher.
> [   12.007120] panel_simple_disable
> [   12.012323]
> [   12.013820] ======================================================
> [   12.019993] [ INFO: possible circular locking dependency detected ]
> [   12.026250] 4.4.0-rc3+ #2755 Not tainted
> [   12.030165] -------------------------------------------------------
> [  12.036417] Xorg/793 is trying to acquire lock:
> [   12.040855]  ((&dp->hotplug_work)){+.+...}[   12.040870]
> [   12.040870] but task is already holding lock:
> [   12.040871]  (crtc_ww_class_mutex){+.+.+.}, at: [<c0383600>] drm_modeset_lock+0x84/0x104
> [   12.040881]
> [   12.040881] which lock already depends on the new lock.
> [   12.040881]
> [   12.040882]
> [   12.040882] the existing dependency chain (in reverse order) is:
> [   12.040883]
> [   12.040883] -> #2 (crtc_ww_class_mutex){+.+.+.}:
> [   12.040887]        [<c0756374>] mutex_lock_nested+0x78/0x41c
> [   12.040893]        [<c038365c>] drm_modeset_lock+0xe0/0x104
> [   12.040896]        [<c0377888>] drm_mode_getconnector+0x168/0x38c
> [   12.040902]        [<c036ae58>] drm_ioctl+0x274/0x408
> [   12.040907]        [<c017cbc8>] do_vfs_ioctl+0x670/0x750
> [   12.040911]        [<c017cd04>] SyS_ioctl+0x5c/0x84
> [   12.040914]        [<c000ff80>] ret_fast_syscall+0x0/0x1c
> [   12.040920]
> [   12.040920] -> #1 (&dev->mode_config.mutex){+.+.+.}:
> [   12.040924]        [<c0756374>] mutex_lock_nested+0x78/0x41c
> [   12.040928]        [<c035b3b4>] drm_helper_hpd_irq_event+0x40/0x150
> [   12.040934]        [<c038e0b0>] analogix_dp_hotplug+0x24/0x28
> [   12.040938]        [<c00450c4>] process_one_work+0x328/0x668
> [   12.040942]        [<c0046334>] worker_thread+0x2cc/0x41c
> [   12.040945]        [<c004bbe8>] kthread+0xf4/0x10c
> [   12.040950]        [<c0010010>] ret_from_fork+0x14/0x24
> [   12.040954]
> [   12.040954] -> #0 ((&dp->hotplug_work)){+.+...}:
> [   12.040958]        [<c007f4ac>] lock_acquire+0x178/0x218
> [   12.040963]        [<c00437d0>] flush_work+0x4c/0x22c
> [   12.040966]        [<c038e45c>] analogix_dp_bridge_disable+0x74/0xf0
> [   12.040970]        [<c0385ef4>] drm_bridge_disable+0x34/0x38
> [   12.040973]        [<c0359044>] drm_crtc_helper_set_mode+0x200/0x424
> [   12.040977]        [<c0359a38>] drm_crtc_helper_set_config+0x6c0/0x988
> [   12.040981]        [<c0373ba8>] drm_mode_set_config_internal+0x60/0xdc
> [   12.040984]        [<c0378938>] drm_mode_setcrtc+0x3cc/0x474
> [   12.040988]        [<c036ae58>] drm_ioctl+0x274/0x408
> [   12.040991]        [<c017cbc8>] do_vfs_ioctl+0x670/0x750
> [   12.040994]        [<c017cd04>] SyS_ioctl+0x5c/0x84
> [   12.040997]        [<c000ff80>] ret_fast_syscall+0x0/0x1c
> [   12.041001]
> [   12.041001] other info that might help us debug this:
> [   12.041001]
> [   12.041002] Chain exists of:
> [   12.041002]   (&dp->hotplug_work) --> &dev->mode_config.mutex --> crtc_ww_class_mutex
> [   12.041007]
> [   12.041008]  Possible unsafe locking scenario:
> [   12.041008]
> [   12.041009]        CPU0                    CPU1
> [   12.041010]        ----                    ----
> [   12.041011]   lock(crtc_ww_class_mutex);
> [   12.041013]                                lock(&dev->mode_config.mutex);
> [   12.041016]                                lock(crtc_ww_class_mutex);
> [   12.041018]   lock((&dp->hotplug_work));
> [   12.041020]
> [   12.041020]  *** DEADLOCK ***
> [   12.041020]
> [   12.041023] 3 locks held by Xorg/793:
> [   12.041023]  #0:  (&dev->mode_config.mutex){+.+.+.}, at: [<c0383d48>] drm_modeset_lock_all+0x50/0xd8
> [   12.041030]  #1:  (crtc_ww_class_acquire){+.+.+.}, at: [<c0383d58>] drm_modeset_lock_all+0x60/0xd8
> [   12.041037]  #2:  (crtc_ww_class_mutex){+.+.+.}, at: [<c0383600>] drm_modeset_lock+0x84/0x104
> [   12.041044]
> [   12.041044] stack backtrace:
> [   12.041048] CPU: 3 PID: 793 Comm: Xorg Not tainted 4.4.0-rc3+ #2755
> [   12.041049] Hardware name: Rockchip (Device Tree)
> [   12.041059] [<c0019914>] (unwind_backtrace) from [<c0014bcc>] (show_stack+0x20/0x24)
> [   12.041066] [<c0014bcc>] (show_stack) from [<c02c4484>] (dump_stack+0x84/0xb8)
> [   12.041072] [<c02c4484>] (dump_stack) from [<c007a2b8>] (print_circular_bug+0x278/0x2cc)
> [   12.041078] [<c007a2b8>] (print_circular_bug) from [<c007e850>] (__lock_acquire+0x14a0/0x1aec)
> [   12.041082] [<c007e850>] (__lock_acquire) from [<c007f4ac>] (lock_acquire+0x178/0x218)
> [   12.041086] [<c007f4ac>] (lock_acquire) from [<c00437d0>] (flush_work+0x4c/0x22c)
> [   12.041091] [<c00437d0>] (flush_work) from [<c038e45c>] (analogix_dp_bridge_disable+0x74/0xf0)
> [   12.041097] [<c038e45c>] (analogix_dp_bridge_disable) from [<c0385ef4>] (drm_bridge_disable+0x34/0x38)
> [   12.041102] [<c0385ef4>] (drm_bridge_disable) from [<c0359044>] (drm_crtc_helper_set_mode+0x200/0x424)
> [   12.041108] [<c0359044>] (drm_crtc_helper_set_mode) from [<c0359a38>] (drm_crtc_helper_set_config+0x6c0/0x988)
> [   12.041114] [<c0359a38>] (drm_crtc_helper_set_config) from [<c0373ba8>] (drm_mode_set_config_internal+0x60/0xdc)
> [   12.041119] [<c0373ba8>] (drm_mode_set_config_internal) from [<c0378938>] (drm_mode_setcrtc+0x3cc/0x474)
> [   12.041124] [<c0378938>] (drm_mode_setcrtc) from [<c036ae58>] (drm_ioctl+0x274/0x408)
> [   12.041129] [<c036ae58>] (drm_ioctl) from [<c017cbc8>] (do_vfs_ioctl+0x670/0x750)
> [   12.041134] [<c017cbc8>] (do_vfs_ioctl) from [<c017cd04>] (SyS_ioctl+0x5c/0x84)
> [   12.041138] [<c017cd04>] (SyS_ioctl) from [<c000ff80>] (ret_fast_syscall+0x0/0x1c)
> [   12.041210] panel_simple_unprepare
> [   12.041359] panel_simple_prepare
> [   12.101638] analogix_dp_reset
> [   12.101879] analogix_dp_init_hpd
> [   12.101897] panel_simple_disable
> [   12.108543] analogix_dp_irq_handler: irq-type 0
> [   12.110452] rockchip-dp ff970000.dp: Link Training Clock Recovery success
> [   12.111900] rockchip-dp ff970000.dp: Link Training success!
> [   12.113384] analogix_dp_init_video
> [   12.215825] rockchip-dp ff970000.dp: Timeout of video streamclk ok
> [   12.215829] rockchip-dp ff970000.dp: unable to config video
> [   12.215832] panel_simple_enable
> ,at: [<c0043784>] flush_work+0x0/0x22c
>
>
>
>


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