Re: [6.3][regression] commit a4e771729a51168bc36317effaa9962e336d4f5e lead to flood kernel logs with warning messages "at kernel/workqueue.c:3167 __flush_work+0x472/0x500"

[Alex Deucher]

On Wed, Mar 8, 2023 at 7:02 AM Mikhail Gavrilov
<mikhail.v.gavrilov@xxxxxxxxx> wrote:
>
> Hi,
> I didn't faced to issue drm_bridge_hpd_enable+0x94/0x9c [drm] but
> fixing this issue leads to warning messages on my laptop ASUS ROG
> Strix G15 Advantage Edition G513QY-HQ007 which has two AMD GPU.
> Discrete Radeon 6800M and integrated in CPU Cezanne Vega 8.
>
> I found bad commit by bisecting:
> ❯ git bisect bad
> a4e771729a51168bc36317effaa9962e336d4f5e is the first bad commit
> commit a4e771729a51168bc36317effaa9962e336d4f5e
> Author: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> Date:   Tue Jan 24 12:45:48 2023 +0200
>
>     drm/probe_helper: sort out poll_running vs poll_enabled
>
>     There are two flags attemting to guard connector polling:
>     poll_enabled and poll_running. While poll_enabled semantics is clearly
>     defined and fully adhered (mark that drm_kms_helper_poll_init() was
>     called and not finalized by the _fini() call), the poll_running flag
>     doesn't have such clearliness.
>
>     This flag is used only in drm_helper_probe_single_connector_modes() to
>     guard calling of drm_kms_helper_poll_enable, it doesn't guard the
>     drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
>     is actually running. Tie HPD enablement to this flag.
>
>     This fixes the following warning reported after merging the HPD series:
>
>     Hot plug detection already enabled
>     WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257
> drm_bridge_hpd_enable+0x94/0x9c [drm]
>     Modules linked in: videobuf2_memops snd_soc_simple_card
> snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common
> snd_soc_imx_spdif adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi
> gov
>     CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted
> 6.2.0-rc2-15208-g25b283acd578 #6
>     Hardware name: NXP i.MX8MQ EVK (DT)
>     Workqueue: events_unbound deferred_probe_work_func
>     pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>     pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
>     lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
>     sp : ffff800009ef3740
>     x29: ffff800009ef3740 x28: ffff000009331f00 x27: 0000000000001000
>     x26: 0000000000000020 x25: ffff800001148ed8 x24: ffff00000a8fe000
>     x23: 00000000fffffffd x22: ffff000005086348 x21: ffff800001133ee0
>     x20: ffff00000550d800 x19: ffff000005086288 x18: 0000000000000006
>     x17: 0000000000000000 x16: ffff8000096ef008 x15: 97ffff2891004260
>     x14: 2a1403e194000000 x13: 97ffff2891004260 x12: 2a1403e194000000
>     x11: 7100385f29400801 x10: 0000000000000aa0 x9 : ffff800008112744
>     x8 : ffff000000250b00 x7 : 0000000000000003 x6 : 0000000000000011
>     x5 : 0000000000000000 x4 : ffff0000bd986a48 x3 : 0000000000000001
>     x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000250000
>     Call trace:
>      drm_bridge_hpd_enable+0x94/0x9c [drm]
>      drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
>      drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
>      drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
>      drm_client_modeset_probe+0x204/0x1190 [drm]
>      __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
>      drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
>      drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
>      drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
>      dcss_kms_attach+0x1c8/0x254 [imx_dcss]
>      dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
>      platform_probe+0x70/0xcc
>      really_probe+0xc4/0x2e0
>      __driver_probe_device+0x80/0xf0
>      driver_probe_device+0xe0/0x164
>      __device_attach_driver+0xc0/0x13c
>      bus_for_each_drv+0x84/0xe0
>      __device_attach+0xa4/0x1a0
>      device_initial_probe+0x1c/0x30
>      bus_probe_device+0xa4/0xb0
>      deferred_probe_work_func+0x90/0xd0
>      process_one_work+0x200/0x474
>      worker_thread+0x74/0x43c
>      kthread+0xfc/0x110
>      ret_from_fork+0x10/0x20
>     ---[ end trace 0000000000000000 ]---
>
>     Reported-by: Laurentiu Palcu <laurentiu.palcu@xxxxxxxxxxx>
>     Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on
> connectors")
>     Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
>     Tested-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
>     Acked-by: Laurentiu Palcu <laurentiu.palcu@xxxxxxxxxxx>
>     Tested-by: Laurentiu Palcu <laurentiu.palcu@xxxxxxxxxxx>
>     Tested-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
>     Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>     Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
>     Link: https://patchwork.freedesktop.org/patch/msgid/20230124104548.3234554-2-dmitry.baryshkov@xxxxxxxxxx
>     (cherry picked from commit d33a54e3991dfce88b4fc6d9c3360951c2c5660d)
>     Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
>
>  drivers/gpu/drm/drm_probe_helper.c | 42 +++++++++++++++++++-------------------
>  1 file changed, 21 insertions(+), 21 deletions(-)
>
> Of course I tried to check the bisect assumption by reverting this
> commit. And I can confirm without commit
> a4e771729a51168bc36317effaa9962e336d4f5e the warning messages do not
> appear within a day.
>
> I attached a full kernel log if someone would be interested to see it.

See:
https://gitlab.freedesktop.org/drm/amd/-/issues/2411

Alex