Date:   Wed, 8 Mar 2023 17:02:10 +0500
From:   Mikhail Gavrilov <mikhail.v.gavrilov@...il.com>
To:     dmitry.baryshkov@...aro.org, laurentiu.palcu@....nxp.com,
        neil.armstrong@...aro.org, tzimmermann@...e.de,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        Christian König <ckoenig.leichtzumerken@...il.com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>
Subject: [6.3][regression] commit a4e771729a51168bc36317effaa9962e336d4f5e
 lead to flood kernel logs with warning messages "at kernel/workqueue.c:3167 __flush_work+0x472/0x500"

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@...aro.org>
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@....nxp.com>
    Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on
connectors")
    Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
    Tested-by: Chen-Yu Tsai <wenst@...omium.org>
    Acked-by: Laurentiu Palcu <laurentiu.palcu@....nxp.com>
    Tested-by: Laurentiu Palcu <laurentiu.palcu@....nxp.com>
    Tested-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
    Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
    Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
    Link: https://patchwork.freedesktop.org/patch/msgid/20230124104548.3234554-2-dmitry.baryshkov@linaro.org
    (cherry picked from commit d33a54e3991dfce88b4fc6d9c3360951c2c5660d)
    Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>

 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.

-- 
Best Regards,
Mike Gavrilov.

View attachment "bisection-__flush_work-warning.txt" of type "text/plain" (2770 bytes)

Download attachment "dmesg.tar.xz" of type "application/x-xz" (34248 bytes)

Powered by blists - more mailing lists